I think 4 months is just a start for you. You have a great mindset....and you won’t disappear from STBXW life as you share kids. Just be the best version of yourself...great dad, etc.
My sitch is somewhat similar in that W doesn’t really have a good reason for D. I have the same character traits in that I was a devoted husband, father, and family man.
You will come out of this ahead IMO....you get the best version of you. While your W will have to be the a$$hole that broke up a family for self serving reasons. She may never acknowledge it to you...but she will know her truth.
Me - 38 W-37 S6 M 10 years T 13yrs BD 3/18 W moves out 4/18 W files 7/18