I know its been some time so I wanted to give an update. The short version is Im pretty sure our marriage is done, not officially as of yet, but her consistent actions doesn't lend to any other conclusion for me.
I dont remember if I touched on it or not, but last month was Leo's birthday and she planned/reserved a paint splatter room for it. Overall no big deal, but she made plans and surprised him with it all for background context. When speaking about my birthday (which was last week) she simply asked what I wanted to do, and I told her "I dont want to have to decide, whatever you all (her and kids) decide is fine. Jump forward a few weeks to my birthday, she takes a half day off work so I go to meet her in that area (rural hometown, where she works is the closest "city") for lunch. First thing Carrie asks, "Where do I want to eat?" Then its "Do I want to do something, is there a movie I want to watch?" Total opposite of what I had said, but it was a month ago and maybe she forgot the conversation so I let it go and we have a good afternoon. The kids did a whole thing for dinner, set up like a Cafe and all that.
Then its late evening, the night of my birthday. About 10pm, she packs an overnight bag and goes to Leo's place (his parents house as a reminder). Her reasoning is because she picked up a 7-11am shift at the ER and doesn't want to get up "early" to get there. We live 30 minutes away at most, and yes he lives 5 away, but really she cant give up 40 minutes of sleep to stay the night with me on my birthday.. So clearly he is her priority and I have been relegated to roommate essentially. We havent had sex in at least 2 weeks (absolutely nothing even initiated on my birthday) and even simply cuddling rarely happens anymore.
As of last week she applied for an apartment, its maybe 3 minutes away mostly for the kids sake. We had talked about the apartment thing as a way for us to be able to have that separate space, but it still sucks. And obviously I dont know for sure, but id guess she only told me because I could tell something was bugging her and I asked very specifically what was upsetting her. She has been doing a lot of lying by omission lately which is why I feel that way. Small example was she was supposed to have a "girls night" with some friends, but after his work shift Leo joined them at the hotel overnight; and she had no intention of telling me.
So tldr recap: Carrie has made Leo her priority and I am basically left behind. She isnt making any real attempt to treat/consider a poly relationship and is only giving him any intimacy (not just sex).