It was either in French or English, that part isn’t clear. It was in color and I saw it during my French class on VHS. (My teacher always showed the weirdest movies)
The plot was a wife that split her time between her two husbands, seeming as if to go away on business trips. Both families, I think, had kids and were both in nice neighborhoods. Partway through, she starts slipping up/confusing the stories that she used with the husbands, just small things like dates and activities. Towards the end the husbands obviously find out, go on a trip together in a small blue car to reconcile or something. I don’t want to give the final scene away.
It was probably some type of romantic movie, or dark comedy? Not sure.