Need closure

Let me start with I know this is wrong. I've guilted myself into near paralysis. But...

I have a one year old and the romance between my husband and I is... lacking. We've had so many conversations about it. I honestly feel like roommates raising a child together. He's my partner, and I love him. I'm not interested in leaving or divorce, but I'm feeling unattractive in my post baby bod, I'm feeling old (I'm only 29), and I was starting to feel like I'd never feel sexy or desired again. Enter an old high school crush, right at my most vulnerable.

He just dropped a line to catch up. We've been friends since the 5th grade, and we stop in to say hi every now and then. Not unusual. He's a single parent, so I started to open up about my frustrations, feeling old and matronly and missing youth, feeling exhausted and strained in my relationship. At first, things started as respectful and encouraging, but we found other reasons to keep the conversation going. Soon we switched from social media chatting to texting each other. Before I knew it we were chatting all day, every day. I was ignoring the problems in my marriage and going to my friend to fill my needs. He made me feel young and beautiful, like I was 18 again. Instead of reminiscing about old times, it transitioned into something more new and adult like. We started sexting, more him than me. I'm pretty shy about that stuff. We even talked on the phone a couple times. I started developing feelings for him. Both of us are committed (I suppose that sounds laughable at this point) to other people, and we live thousands of miles apart, so we were never interested in taking the next step, but suddenly, after almost a year, he decided he didn't want to talk anymore. He ghosted on me. Shortly after that he proposed to his girlfriend. I haven't heard from him and to stop myself from doing something I'll regret, I unfollowed him on social media and deleted his number.

We always said we would have a conversation when one of us wanted to walk away from the friendship, emotional affair, we created. But he didn't. It's been months since we've spoken and I can't stop thinking about him. I've even managed to work on my marriage, and I feel like I am back on track with my husband, but I keep wondering.

I don't have any closure. I think that's the problem. At this point, I'm angry with him. We were always open and honest with each other, so I can't understand why he would bring me to the point of attachment and then vanish. Was it all a joke? Living out some high school fantasy, and when he realized he could have it if he wanted, he was done? Much more likely, it's that he decided to commit to his girlfriend and didn't want to be in the same place as me, attached to someone outside of his marriage. I often told him I didn't want that for him. But then why didn't he give me a heads up?

I don't know what to do to get my head out of the clouds. I want my husband. I'm not interested in leaving him, but I don't know how to get my head right. Any advice? I understand if it also comes with judgment. Just remember there's always more to the story. I couldn't possibly post it all.