To think if you involve someone in your personal life

[PinkGlitter123]

And problems and cry to them regularly that you can't be annoyed if they continue to have an opinion after the event is over and you are feeling better (Even if you don't like that opinion.)

Depends.
If I was in a shit relationship and I cried to you and then I ended it I wouldn’t want someone to keep reminding me of it.
If I had robbed a bank and cried about it to you and then considered robbing a bank another time then I would expect to have to listen to your opinion.

Friend shagging a married man, OP?

Depends.

Sometimes friends think 'being there for you' means that they are able to voice whatever opinion they want, for however long they want, as if you are in some kind of debt to them. I don't think that's a functional friendship.