Hang in there! You have a wonderful little girl to live for and whom you can focus your attention on. That is the biggest blessing.
I do think you need to let go. Not just let go of your W, or the MR that was, but let go of the expectation that you can EVER make sense of this situation. It doesn't serve you to focus on that, and the lack of a rationale behind it can/will drive you nuts if you let it. Sh#t happens. The longer you stare at the past the more you don't have your eyes on the present. Maybe that's the answer. It's hard to let go and when you turn your mind towards it, it is easy to once again fixate on the object (W, MR) that you are trying to release. So, instead focus on the present, the life you have, the life you and your daughter share.
W 34 Me 42 Married 7 years together 8 0 kids 1 beloved dog BD 4/6/2018 I moved out 4/7/2018 I moved back in alone 8/05/2018 I file 3/06/2019 D official 5/7/2019