Ex in a "serious relationship" after 3 months apart??

[Saga]

Hey everyone,

OK, I have posted before but to save you time I'll give a brief summary of the past few months:

My ex and I broke up just before Christmas. He initially said we need to take a break, and I was kind of taken by surprise though we had had a bad argument. A few days later he wanted to work everything out, but after some things had happened and I had those few days to think I said I really didn't think we could work it out. Sooo we talked maybe once a month and up until Friday he'd always said "if you ever need anything you can always call me." We didn't exactly maintain a friendship, but I'd say around early February he was saying he heard a song I used to play on the piano and he almost cried, and I wasn't a bad girlfriend, if anything ever happened to me it would tear him up, and even ended with "I love you."

Up until about a year ago, this guy was an alcoholic. We would have broken up then because I was fed up (after 14 months of dating). Well he stopped drinking that day and started going to AA and stuff, and I went too to be supportive. Meanwhile, before that I had written a song about his drinking. A band and I performed the song yesterday, and Friday was the 1 year mark of his sobriety so the song made me think of that. I sent an email merely saying "Congratulations on 1 year" because he'd seemed pretty pissy the last time we talked (about 6 weeks ago), so I kept it brief. He responded with "Thank you for the letter. I am in a serious relationship and feel our conversations are no longer appropriate." I know this shouldn't bother me- it's a part of life...but we haven't even been apart 4 months. To go from loving me 2 months ago to "seriously" loving another woman 2 months later and cutting me off...I just don't know. On a sidenote, our relationship was interracial and long distance and he met this woman online who happens to be my race and from the city I used to live in (before I started school) where he met me (online), so I'm not sure if that's coincidence or if he's seriously "replacing" me. I don't think I'm jealous- I mean there's NO WAY the 2 of us could be together. He's definitely got some issues to work out. I had some too, but I am still single because I know I have more important things to worry about right now (school, finding work, myself in general, performing). I'm casually dating but there's no way I'm hopping into anything serious yet. I guess my question is is it possible to fall in love that quickly? Is he just trying to make me jealous? I don't know, and I'd like to see what some men think.