Trying to follow your story, there's a lot to unpack:
1. Military. First, thank you for your service. With the deployments and everything, this can of course be extraordinarily challenging to a MR.
2. Fertility. It sounds like you had fertility issues. While this is challenging for both H and W, it can be identity shattering for the W. Did your W deal with this or did she stuff her feelings/suffer depression?
3. Children. Congratulations on your adoptions. How did your W adjust to motherhood/how did you adjust to fatherhood/how did that affect your R?
4. Career/money. It sounds like you put a lot of your interests first without your W's input or consideration, is that correct?
5. OM. It sounds like you've heard a lot and suspected a lot. What is confirmed? Is it an EA or a PA? What does she get from OM?
6. Separation. You are legally separated now. Is that going to be a long term arrangement or are there discussions of divorce?
What should you do?
1. You are right that your primary focus should be on you and improving you, which is the only thing you can control.
2. You are right that your secondary focus should be on your kids; you have them 50% of the time which is great. You said you have improved on being a dad, which is great, keep up with that.
3. You are concerned that it's hard to move the needle as (a) you have very little interaction with your W and (b) she is still involved with OM. You are right, so you need to focus on #1 and #2 above and when you do interact, make it a positive one (look good, smell good, be positive, act as if, no R talks).
Gordie 40s W 40s M20+ kids 2016 BD W fantasy affair w OM1 I do everything wrong 2017 I start to DB W says TLTL files for D PA w OM2 2018 I do LRT W drops filing and OM2 situation slowly improving