Concerns about my bf’s relationship with his ex wife

I’ve been seeing my bf for a few months. He’s been divorced a little over a year and he and his ex share custody of their son (6 yo).

One of the major issues that led to the divorce is that she really lost herself in being a mom and they no longer connected as people or a couple - everything was just about their kid.

They had an amicable divorce but he has said he doesn’t really see them being friends right now…they get along but the communication they have is about their kid. I have told him that I’d be supportive of them being friends eventually since they will always be in each other’s lives.

But I’m starting to have some concerns and I’m not sure if I’m getting worried about nothing.

For one, sometimes she sends photos or things that are for their kid (they are too young to have a phone) but it’s fun/silly stuff. I definitely think it’s good for her to stay in touch with their kid but looking over and seeing her name on his phone all the time makes me a little anxious. I feel like, if they are having that much communication it could easily move from talking about the kid to talking to each other just as people and reconnecting on some kind of romantic level.

I also think that the issue of her becoming so absorbed in motherhood that she lost herself is likely to be going away now that she has some time to herself. My bf has mentioned she’s gone back to the gym and started doing more things for herself (the type of things he wishes she did while they were together)

So I guess I’m wondering if maybe he’s going to develop romantic feelings for her again. He has said he’s no longer in love with her but…who knows. And I mean…if the option to get back together with his ex/mother of his child was available in a healthy way…I wouldn’t want to stand in the way of that.

So…I’m just a little anxious and insecure right now. I’d like to know what are some signs I should look for that might spell the end of my relationship with him. What is healthy communication between coparents? And where is the line? I don’t want to say he can never talk to her or ask her about her day or her life. I just…don’t want to be blindsided.