Post was deleted on r/relationships so posting here thank you

TL;DR; : my wife has said she might love her high school EX more and probably would leave me if we didn’t have a son

My wife (24F) and I (25M) have been married for 3 years. We have two kids, one together and her daughter (my stepdaughter). We’ve had such a good life together. We’ve had our ups and downs but every marriage does.

This past weekend we went to our home state, to see friends from high school and go to a ren fair. Her high school boyfriend is one of our friends and in the past she has told me she doesn’t have feelings for him. But she misses the life she had with him. Like no kids, and no responsibilities. So I understood that feeling of missing her life with him.

During the Ren fair she was unknowingly avoiding me and spending a lot of time with him. I noticed it a couple times but didn’t want to believe it or think anything of it. On of our friends noticed it and pulled them both aside and told them he noticed it. After ren fair she spent the rest of the night with all of our friends. While I went back to my parent’s home to be with the kids.

The next day, after she came back from hanging out with all them. she seemed fine and didn’t seem off.

It’s now Monday and we are back home. She came home from dropping our daughter off at school crying. And that’s when we sat down and she told me about what happened when she was with our friends.

She tells me nothing physical happened between her and her EX. But she said she still loves him and it really hurt her heart to be leaving him. She also said if we didn’t have our son or any thing else stopping her from leaving she probably would have left.

Now all I can think about is the fact that she loves him more since she would obviously leave me. Our son also has a terminal illness and is only expected to life to 10 years old. So all I can think about is her leaving if we lose our son. And is our marriage completely ruined now, that now she realizes she loves him more. Any advice would be great I can’t stop thinking of the worst. We’re currently taking a distance from each other she’s out doing errands while I’m home with our son. I just don’t know what to do anymore. Thank you.