What is with these men and boning the hired help?!

Gavin Rossdale was cheating with family nanny Mindy Mann for three YEARS before Gwen Stefani uncovered their affair, the newest issue of Us Weekly reports.

The No Doubt singer discovered explicit exchanges between her then-husband and Mann on a shared iPad after being alerted by another staff member. The damning evidence? Nude photos of Mann and texts about meeting up for sex!

"The iPad was linked to Gavin’s phone. One of the other nannies discovered the exchange and told Gwen," a source told the mag. When confronted, the father-of-three initially tried to brush off the infidelity as "flirtation" but ended up confessing shortly after. "[The confession] completely devastated her. She was mortified, livid, and embarrassed," the source added.

The Voice coach discovered the truth this past February and filed for divorce in August. She has moved on and is now dating Blake Shelton, while Rossdale has largely stayed off the radar.

Maybe Gwen and Jen Garner could grab coffee and swap stories of betrayal?