Im drowning

Ok I have to sum this up but there's SO many deep layers to it. Main issue, I think I'm still in "love" with my ex boyfriend. It's been FOUR years since we've had any contact. It ended badly. We're both married and have kids. I've legit never stopped thinking about him ever. I just recently saw him at Walmart and almost had a panic attack, I had to leave. I also just heard his wife cheated on him and he added me on Snapchat. Basically a snow ball of recent events. But I have yet to stop wondering what if, not a day goes by where I don't think he's the one legitimately for me. I don't know what to do? Maybe I just need closure but what does that look like? Send help and prayers. I believe in soulmates and I swear he's mine. I'm drowning in emotions. I can't be the wife my husband deserves if I feel this way 😭😭😭😭

Side bar- My husband is a really great husband and dad but I'm a POS for secretly being infatuated with someone else.