It's Complicated
(2009)

Jane (Meryl Streep) has several flings with her ex-husband Jake (Alec Baldwin), one of which is discovered by Adam (Steve Martin) who realizes that she still has feelings for her ex.

Jane admits to her whole family about the affair. Jakes wife, Agness (Lake Bell) catches on and leaves him.

After some painful truths about Jane not wanting to get back with Jake, Jake accepts and the last scene is with Jane trying to reconcile with Adam.

We are lead to believe everything will be okay between Jane and Adam. 

Thanks Steve!