Having trouble dealing with an ex's post break-up conduct

In March 2005, I began dating a woman I'll call Carey. I thought she was a 'good girl'. She was religious, went to Bible study, etc. We were both virgins, and remained so because she didn't want to have sex before marriage. We fooled around in other ways, but never had penetrative intercourse.

At first, the relationship was fun and fresh, but as we got deeper into it, Carey grew more and more paranoid and passive-aggressive. She would constantly think that our relationship wasn't going well, she would cry for no reason, etc. Another sticking point was that Carey had this huge issue that she couldn't discuss with anyone. It would cause her to get upset and cry. I felt bad, because she wouldn't tell me what was going on and would cry about it.

I admit that I was not faultless. At the beginning, I had told Carey some lies about my past to seem more experienced than I actually was (she was my first girlfriend). I decided to come clean about my lack of experience around the 4 month mark, because I wanted our relationship to not be built on lies. I also feel like I sometimes tried to solve all of her problems, and might have been a little more brusque with her than needed.

I attempted to break up with Carey in August 2005, but she was very emotionally and mentally fragile, so I held off. These warning flags were there all through our relationship. She didn't have many other friends, was very needy and clingy, and counted on me to keep her company, whether in person or on the phone.

Anyways, we ended up breaking in November 2005. We attempted to remain as friends, but Carey had the idea that we would get back together again. Whenever we met, it was drama, and she finally confronted me about where our relationship was in February 2006. I told her we weren't going to get back together. She cursed me out really badly when this happened. After a couple of more similar calls, I decided it would be best to break off all contact. So, we agreed to meet and exchange our things. At our meeting, she verbally tongue lashed me for an hour, blaming me for all that had gone wrong, crying, asking if we could try to make it work, etc. She ended up pushing me out her door when I was leaving, and then made as if she was going to run me over in her car in the parking lot.

Subsequent to the breakup, I worried about Carey's well-being. We had one mutual friend, and I stayed updated on her life. A few months passed and I found myself not thinking about her as much. I had a couple of rebound relationships which didn't go anywhere. I met a wonderful girl who I love with all my heart this past March. We get along fabulously.

But, in speaking to mine and Carey's mutual friend, I found out that soon after we cut contact, Carey got into a friends with benefits relationship with a guy at work. She also dated another guy who had a kid shortly after that. It seems like she's been hopping from man to man ever since we broke up. This totally went against the sort of person I thought she was. Our mutual friend said it's because Carey can't deal with being alone.

I'm having a really hard time dealing with her post-breakup conduct. I feel like she was not the person I thought she was. I also find myself thinking about whether she's out having sex with all these guys. We never had sex because of her feelings on the issue, but it seems like she may have compromised on that if she's going with so many different guys.

I'm seeing a therapist who's helping me deal, but I admit it's been tough. My new girl has been very understanding, but I don't want my inability to deal with my ex's conduct to harm my new relationship.

If any of you guys (or girls) can offer advice on how to deal, I would really appreciate it.