Is it wrong for me to avoid him and feel jealous too? Please help..?

Okay so there's this guy that I've known for about a few years. We talk, text, hang out, etc all the time for as long as I've known him and I care about him and trust him more than any other guy I know. Basically, he's my closest guy friend. But, back when we were sort of in a flirty stage, we did some things that I'm not proud of. Well, I mean, we kissed like twice but it was while he had a girlfriend (I ALREADY KNOW I'M A TERRIBLE PERSON, SLUT, BAD FRIEND, WHATEVER! the kiss happened over a year ago, don't yell at me, please!!) and not only did we kiss but whenever we were hanging out, he'd make up random excuses to touch my legs and to put his arms around me, he'd compare me to his girlfriend and call me hotter, stuff like that..Anyways, though, after that flirty stage ended, his girlfriend found out, she told everyone, people hated me, blah blah blah. But now, after everything, she wants him back. And he wants her, too. Now, don't get me wrong, I want him to be happy! But right when he told me they might get back together, I had this awful feeling like a punch in my stomach and I guess it was jealousy, too. But why would I be jealous? I seriously don't like him at all! I might've when we kissed but now we're completely platonic. And he told me this like a week ago, I haven't spoken to him since then. Actually, I've been avoiding him. Is it wrong for me to be jealous and avoid him? I mean, I'm not angry with him, I just don't want to risk us getting flirty and ruining the relationship again...ahhh, I don't know what to do..help?