Undeclared work and the ex's new cohabitation: how to prove them with valid evidence.

You keep paying the allowance, but the ex-spouse who declared themselves «without income» before the judge goes out to work every morning, posts dinners and weekends on social media and has just changed cars. It is one of the most frequent - and most frustrating - situations in family litigation: everyone knows, no one can prove it. And in court, what is not proven simply does not exist.

We covered the legal prerequisites for revising the allowance - when it can be requested, through which procedure, what must have changed - in the guide to the revision of the maintenance and divorce allowance. Here we get into the operational side, from the standpoint of those who build this evidence every day: how to prove that the ex-spouse is working under the table, is stably cohabiting with a new partner or maintains a lifestyle inconsistent with their declared income - and which mistakes can ruin everything.

The signs that the declared income does not add up

Almost all of our assignments in this field start from the same point: a perceived inconsistency, repeated over time. The recurring signs our clients report:

• A worker's routine, an unemployed person's status: they go out every morning at the same time and come back in the evening, yet formally they are unemployed or on a minimal part-time contract.
• Spending that the declared income cannot explain: a new car, home renovations, holidays photographed and posted online, designer clothing and accessories.
• «Family» businesses: the shop or the business registered in the name of the new partner or a relative, where however it is always the ex-spouse standing behind the counter.
• The shadow partner: a relationship that has lasted for years, a car always parked outside the house, but no declared cohabitation - because formalizing it would mean losing the allowance.

Be careful, though: these are clues, not evidence. A screenshot from Instagram or an acquaintance's account is not enough to ground a petition: what is needed are precise, repeated elements documented with method. This is exactly the step where a professional investigation makes the difference.

How undeclared work is documented: field observation

Proof of undeclared work is never a single snapshot: it is the reconstruction of a pattern. The protocol we apply in investigations for the review of the maintenance allowance combines several layers:

• Preliminary OSINT analysis: open sources, social profiles, online listings and reviews (those who work «under the table» often advertise anyway), company registry searches to surface directorships, shareholdings or businesses registered to nominees.
• Static and dynamic observation: stakeouts and tailing in public places or places open to the public, to document entry and exit times, the locations where services are performed, contacts with customers and suppliers.
• Repetition over time: the same scene documented on different, non-consecutive days. It is the recurrence - not the single episode - that proves a habitual work activity rather than an occasional favor.
• Georeferenced photo and video material: every piece of evidence with a certain date, time and place, organized into an analytical chronology.

Proving more uxorio cohabitation: what is really needed

Since the ruling of the Joint Divisions (Cass. SS.UU. n. 32198/2021), the beneficiary's stable cohabitation directly affects the divorce allowance. But «stable» is the key word: a romantic relationship, even a steady one, is not enough. The judge looks for the indicators of a shared life project:

• Continuous cohabitation: overnight stays documented with weekly recurrence over a span of weeks or months, not a single night.
• Shared management of everyday life: grocery shopping together, taking the children around, shared pets, having the keys to the home.
• Duration and social recognizability of the relationship: the couple attending family and social events as a couple.

The dossier reconstructs these elements through observations distributed over time: it is the only way to overcome the classic defensive objection («he's just a friend who sometimes stays over»).

Lifestyle as an indicator of hidden income

When undeclared work cannot be observed directly - activities carried out on private premises, remote consultancy - the main route is the gap between spending and declared income. Trips, stays in luxury facilities, vehicles, recurring purchases: every documented item contributes to building a serious, precise and consistent presumption of a real economic capacity higher than the formal one. On this basis the judge can rule even without the «smoking gun» of the off-the-books employer.

Do-it-yourself evidence that backfires

The flip side: badly gathered evidence is not neutral, it is harmful. The three mistakes we see most often:

• A hidden GPS tracker on the ex's car: it can amount to a criminal offense and renders the evidence unusable - we covered it in detail in the guide on when a GPS tracker on your spouse's car is a crime.
• Unauthorized access: getting into the ex-spouse's phone, email or social profiles is a computer crime, regardless of what is found there.
• Amateur tailing: without authorization and without method you risk a stalking complaint and you «burn» the subject, who from that moment on will change their habits, making a professional investigation far more difficult.

An investigator authorized under art. 134 TULPS, by contrast, operates to protect a right in court, within the boundaries of the GDPR and of the provisions of the Garante for personal data protection: the evidence remains admissible and the opposing party has no grounds to have it declared null. The full picture of our credentials is in our certifications and prefectural authorizations.

From dossier to petition: what happens next

At the end of the observation we deliver a technical report with an analytical chronology, geolocated photographic material and the signature of the investigation manager, structured for filing in the revision proceedings; our investigators are available to confirm its contents as witnesses at the hearing. For the legal prerequisites of the petition - justified intervening reasons, the differences between the maintenance allowance and the divorce allowance, typical scenarios - we refer you to the dedicated guide to the revision of the allowance, to be read together with your trusted lawyer.

Milan, Monza e Brianza: deployment within 24-48 hours

From our headquarters at Piazza Don Mapelli 60, Sesto San Giovanni, we operate across the city of Milan, the North-East hinterland, the province of Monza e Brianza and the Cinisello Balsamo-Vimercate-Lecco axis, with deployment normally within 24-48 hours of the feasibility assessment and no travel surcharges within the serviced area. Our «Km Zero» policy provides for a defined budget crystallized before the start: no surprise costs at settlement.

If the ex-spouse's numbers do not add up, the first step is not a petition: it is understanding whether the evidence can be built. Request a confidential preliminary interview with our Family Law division - covered by professional secrecy and with no commitment whatsoever.