It's a kind of a blurry flashback of some scenes overviewed in the nineties. The woman is talking with an older man than her who just slept with her. The man is still lying in the bed and she's wearing a t-shirt or some lingerie and maybe she kisses him. After, she returns at home and she's surprised to find her husband in bathroom. He's looking himself in the mirror and find a white hair on his head. They're talking and he says something like "Do it honey" (I didnt's see that in original english version, so it was Fais-le chérie) and she begins to remove her clothes.

It's really weird to remember this so precisely.

I finally found it by keyword research on imdb. It was Final Analysis... stupid Richard Gere and his premature gray hair, it deceived my memory.