What’s the name of that movie?

Hello. As long as I remember, I think it was based in New York City in the present time. It was filmed maybe from 2008/9 till 2017.

It’s about the engaged couple and they are celebrating their engagement with friends. Friends tell them that, they are first love and they won’t sleep with anyone except themselves for the rest of their lives. So they decide to sleep with someone else just for the experience. She slept with one man from a band from a bar where he was playing. he gave her his number, she threw it away, but then she kept it. It ends with marriage proposal, she says no, as she is still young and wants to experience with other people. can you please find that movie for meeeee. thanks