I think you have what is called limerence.
my high school boyfriend and I were obsessed with each other. We were each others “firsts” and were together for almost 3 years before he went off and joined the marines - I was devastated. We briefly re-kindled in my mid-20s but it was apparent we’d grown to be different people and as a now, adult “looking for marriage” age, he wasn’t the one for me.
I think if we’d not had that rekindling when I was a little older, where I could see him in a new and more mature light, I’d possibly have limerence over him.
Your husband, who you say you adore, has proven time served what a good dad, husband and supporter of yours he can be. (I mean, who doesn’t kick off to their wife speaking to an ex?!)
Your ex, who you dated when your pre frontal lobe wasn’t even formed and likely didn’t even live with, hasn’t proven anything. He’s met you for coffees and likely texts/calls you and says the right thing. What’s he like with house keeping, will he be kind to your kids (imagining they’d accept him, which they won’t), would he be nurturing to your parents and let you do everything you enjoy doing now. Will he help around the home, want the same holidays as you, enjoy doing the same activities you enjoy now ok weekends?
it’s a lovely thought that you can sail off and build a new life on the ashes of your old one, but it’s not that clean cut and you need to take off your tinted spectacles. If you were a man, we’d all be saying “the grass isn’t always greener” and I think you need to snap out of thinking it is.
You know your husband and family deserve better. You are at this point because of YOUR encouragement of this behaviour so you should feel bad, but the only thing to do is cut him out your life and say a polite goodbye. You THINK you love him but you did as a 19 year old and currently think you might because you see him randomly for coffees and speak occasionally. Do you love him at his/your worst and lowest? Unlikely! Cut him off. Be thankful you haven’t imploded your own life and I’d suggest you fess up to your husband that (1) you’ve cut him off and (2) it’s because he confessed feelings for you that you don’t want to encourage. Your husband can then police you not contacting him again. (Think of it as telling your friends/parents that the bf you keep taking back cheated on you - once others know, there’s no return) He isn’t owed anything because he’s strung some other poor woman along for years. This isn’t romantic, it’s odd. You will burn your whole life down then realise he’s not Prince Charming. Men do it all the time!!
you’ve got yourself in this position, so get yourself out of it.