It seems like the situation is a classic case of cold feet to me. HE tracked HER down about 3 months before marriage? Feelings of love from when they were 10? Give me a break. I couldn't tell you more than maybe 5 people I had a crush on when I was 10. It sounds like he got scared. Started thinking about this girl and emailed her. And the fact that he hasn't seen her in over 2 decades leaves more room to the imagination than an ex he hasn't seen for maybe 5 years. He can put her up on a pedestal because he has absolutely no idea what she is like now.

I really wouldn't worry unless he tries to lie about it. If he went and cut off communication and you can verify that and he genuinely seems upset that he hurt you then I would chalk it up to being afraid to get married. When my bf wanted to move in with me all of a sudden every guy could be the guy of my dreams. Just commitment is extremely scary.

Go to him and let him know that you understand if he has second thoughts or weird feelings about entering into a lifelong commitment. Ask him what is REALLY going on and try not to sound like you're accusing him. If he opens up to you and talks about it, I'd say you have nothing to worry about.