Maggie's Plan (2016)

Maggie is a sweet girl who has had longitudinal problems sustaining a relationship.  She decides that she is ready to have a child, and she has no intention of waiting until she finds the right guy.  She has an acquaintance from college that she asks to help her, and he is agreeable to being the donor.  So that is Plan A.
Enter Ethan Hawke (John), who is married with two kids and a little bit self absorbed.  As is his lovely wife, Julianna Moore (Georgette).  Maggie is full of warmth and confidence in who  John is, far more so than his wife, and he falls for that and she falls for him.  This affair is consummated on the very day that Maggie has self-inseminated herself with her college friends sperm.
Fast forward a couple years, Maggie and John are married, and Maggie is doing literally everything.  She is raising the kids (hers and John's), earning the money, and ferrying everyone around, and one say she looks up and doesn't want to do it anymore.  Never fear, she has a plan for that too.  It is a movie that is a little bit fun, a little bit serious, and a little bit mysterious.