Cohabitation with a new partner
Your former partner has a new relationship and visible patterns may indicate factual cohabitation or a durable shared household. Legal qualification is for your lawyer and the court.
Private clients — Spousal maintenance
Alimony investigation in the Netherlands: suspected cohabitation or undisclosed income
Does it feel unfair to pay maintenance while your former partner may be cohabiting or concealing income? Recurring indications can create frustration and doubt. Dutch Detective Agency helps you move beyond assumptions by carefully examining relevant patterns and circumstances and recording the facts in a clear report for discussion with your lawyer.
Typical situations
Two situations account for almost every alimony enquiry we receive.
Undisclosed income or side activities
There are indications of structural work, a business or side activities that were never declared, while the reported financial capacity does not match. Factual observations about work patterns or business activity may then be relevant.
Preliminary investigation: establishing whether a full investigation is feasible
Before investing in a full alimony investigation, you may start with a focused preliminary investigation. The preliminary investigation forms the first phase of the full investigation and is intended to establish whether there are sufficient factual grounds to continue.
What do we investigate during the preliminary phase?
During the preliminary investigation, we conduct surveillance at agreed times and factually record how often your former partner and the suspected new partner are observed together.
The purpose is to establish whether they are together on more than three separate days during the agreed observation period. When this is established through surveillance, it provides evidence of factual cohabitation and sufficient grounds to proceed with the full alimony investigation.
Time spent together at either residence is relevant
For establishing factual cohabitation, it does not matter at which residence the former partner and the new partner stay together. This may be at the former partner's home, the new partner's home or alternately at both residences. Joint days and overnight stays at either residence may form part of the factual pattern.
The investigation therefore focuses on their actual presence and behaviour at both relevant addresses. Being officially registered at different addresses does not automatically exclude factual cohabitation.
What happens during the follow-up investigation?
If the preliminary investigation establishes that the former partner and the suspected new partner are together on more than three separate days, the full alimony investigation may continue.
During the follow-up investigation, the cohabitation is investigated further and documented over a longer period. We also investigate and document the other circumstances relevant to Article 1:160 of the Dutch Civil Code:
- a lasting affective relationship;
- a shared household;
- mutual care.
The preliminary investigation therefore provides the initial evidence of factual cohabitation. The follow-up investigation is intended to substantiate the cohabitation further and document the other relevant circumstances carefully.
Part of the final investigation report
If the investigation continues, the observations and findings collected during the preliminary investigation are incorporated into the final investigation report. The preliminary work is not lost and does not need to be repeated during the follow-up investigation.
The report includes the relevant observations from both the preliminary and follow-up phases. Findings are recorded factually, with dates and in a traceable manner, so that the client and their lawyer can assess them.
Full financial credit
The preliminary investigation is not an additional investigation charged on top of the total investigation costs. It forms the first phase of the full alimony investigation.
If the client proceeds with the follow-up investigation, the amount already paid for the preliminary investigation is credited in full against the total agreed investigation costs. The client then pays only the remaining balance.
If the investigation does not continue after the preliminary phase, the client receives a factual summary of the surveillance conducted. The amount paid then covers the preliminary investigation already completed.
Article 1:160 Dutch Civil Code
This explanation is general and informative. The legal assessment of your case belongs with a Dutch family lawyer.
Article 1:160 of the Dutch Civil Code provides that the obligation to pay spousal maintenance ends if the recipient remarries, enters into a registered partnership, or lives with another person as though married.
Dutch case law interprets that last criterion strictly. There must generally be a lasting affective relationship in which the partners run a durable shared household and mutually care for one another. All of these elements must be made plausible; occasional overnight stays or a shared holiday are not enough.
Because the consequence is far-reaching and irreversible — the maintenance obligation ends permanently — Dutch courts set a high bar for factual substantiation. We therefore make no prediction about outcome; we supply facts on which your lawyer can build a position.
What can be established, and what cannot
Clarity about limits belongs at the start of a matter, not at the end.
What can be documented
- Presence patterns at an address across several spaced observation windows.
- Behaviour visible from the public road that may indicate a shared household.
- Vehicle use and movements consistent with a fixed place of residence.
- Publicly accessible register data, such as Dutch Chamber of Commerce filings.
- Visible, structural work or business activity.
The limits of the work
- An objective outcome: you receive a factual report of what could and could not be established during the investigation.
- Strict proportionality: the effort remains in proportion to the interest and purpose.
- Necessity: where a less intrusive route exists, that route comes first.
- No entering homes, no listening devices, trackers or access to accounts.
- No financial data from non-public sources; bank records belong in the legal procedure.
- No legal advice: assessing your position is your lawyer's role.
How facts are recorded
Findings are only usable when they are objective, traceable and recorded within applicable privacy limits.
Objective observation reports
For each observation window we record what was factually observed, in neutral wording and without interpretation or conclusion.
Date and time logging
Every observation carries a date, time and location, so that any pattern remains traceable and verifiable.
Photographic material within privacy limits
Images are made only where necessary and proportionate, from public space, and limited to what the investigative purpose requires.
Data minimisation
We collect and retain no more data than necessary, in line with the GDPR and Dutch data protection standards.
Reviewable final report
The report separates facts from any uncertainties, so a third party can weigh the findings independently.
Confidential handling
Case files are handled confidentially and shared only with you or the lawyer you designate.
Working with legal counsel
An investigation report is not a legal position but factual substantiation. Your Dutch family lawyer decides whether and how the findings are used: in correspondence with the other party, in an application to end or modify spousal maintenance, or in proceedings before the court.
Early coordination pays off. When counsel indicates which facts are legally relevant, the investigation can be narrower, shorter and less intrusive. On request we align the written plan directly with your lawyer and deliver the report to the firm.
International clients can instruct Dutch Detective Agency when the relevant person and facts are in the Netherlands. Eerste contact and communication are available in English, and reporting is prepared for review by the client’s lawyer or adviser.
How we work
Four steps, with a clear decision point before any investigation takes place.
- 01
Eerste contact and assessment
We discuss your situation, the indications and the objective, and test the legitimate interest, proportionality and necessity of the proposed work.
- 02
Written plan
You receive the objective, methods, expected effort and cost framework in writing. Nothing starts without your approval.
- 03
Local execution
Discreet execution in the Netherlands by the investigator, with interim feedback where findings warrant it.
- 04
Objective final report
A factual, dated and traceable English report, with images where appropriate, for review by your lawyer or adviser.
Frequently asked questions
Do not remain alone with that sense of unfairness
Briefly outline your situation by telephone or email. We will listen and discuss honestly which investigation may provide useful clarity.
Or email info@dutchdetectiveagency.com. International callers dial +31 85 060 0100.