Help me find this movie: something about a man with a fake marriage to a gay woman

Hi everyone!
I remember part of a plot/subplot of a piece of media I’m not totally sure it’s a movie (could be a tv series!), and not being able to remember the rest/find where it’s from is driving me crazy, so I would appreciate a bit of help.

What I remember is this man who everyone knows is married (possibly his wife works with him or she is really present in his everyday life) who falls in love with a woman (who possibly reciprocates); his marriage is actually fake thou: he is married to a lesbian woman (possibly bisexual, anyway she has a relationship with a woman), to protect her, and they sleeps in different rooms and she has a partner who takes her often out.
The story it’s set in the past, maybe the fifties? But could also be the seventies?

I clearly remember the scene where the men is sleeping in his room and the wife’s partner comes to pick her up, but he is the one opening the door and so they chat a bit.
I also remember him being worried about his wife/friend because she nearly gets caught being with the other woman in some public place…maybe a pub or a movie theatre?
Also I remember him and the wife/friend talking about him having this crush for the new lady and the possible outcomes of this.
If I remember correctly, he has never fallen in love before, therefore his acceptance of the deal of the fake marriage.

The more I think about it, the more these scenes get clearer in my mind, but I seem unable to add any other detail to the plot.

Thanks everyone!