Help! Movie about a separated couple coming back together

Second time I am posting. This is driving me nuts trying to find this movie. Please help. This is a romcom. It’s not a drama or anything like that.

It’s about a husband and wife. He cheated on her and it appears they are separating. They’re in their late 30’s or 40’s.

I believe their kids are at camp and they are going on separate trips during the break. He leaves on his old motorcycle, she is going on some outing (I believe) with friends.

His motorcycle breaks down. He calls her and she picks him up. The repairs will take days so she takes him to his dad’s where they stay.

They start reconnecting and she ends up wanting to have a night with his non-biological step brother. They agree to threesome instead and his step dad walks in on them before it awkwardly started.

There’s also a scene where they “getaway” to treehouse and do hallucinogens to try and connect.

There’s another part where she finds something and thinks he’s cheating and she leaves, goes to a bar, then reads a heartfelt letter for her to meet him at a bridge where she has always been afraid to jump in he water. She goes. She asks him if he remembers their wedding vows and, as a surprise to her, he does. The movies ends with them jumping in the water, hand in hand.