<human>: Summarize the given text in a few sentences.

My girlfriend and I met this past August in our Freshman year of college.  We hit it off immediately as friends, but always had this weird relationship that teetered back and forth between friends and something more.  We finally decided to start dating in February and these past 4 months have been the best of my life.  I feel that we are a really good match for one another and can honestly see this relationship reach new heights.

That being said, she had one major boyfriend before me and she dated him for 3 years, but with a couple breakups.  She wasn't exactly faithful to him, having cheated on him a few times.  What's worse is that he only knew about the first time and decided to forgive her for it.  Admittedly, their relationship was strained because he went off to college while she was still in high school, but that doesn't excuse her actions in my opinion.  

She tells me that I'm a much better boyfriend than her ex was and that she was unhappy when she cheated on him.  But she seems to blame him for her unhappiness at the time and not take responsibility for her actions.  She seems ashamed of what she did, but she never admits total responsibility for her actions.  This bothers me, because I don't feel like she was really sorry for what she did.  We have talked about this before, but I feel like I'm trying to make her feel bad about herself.

The reason this has been bothering me lately is because she has been out of the country on a trip.  She tells me that she could never dream about cheating on me because I'm so perfect, but I feel like that isn't the response I want to hear.  I'm very conflicted.  I completely trust her and feel like I shouldn't worry, but this small part of me is scared.  I have strong feelings for her and I am worried that I am going to get too attached before I get my heart broken one day.  I feel like a jerk for thinking this, but I don't know how to bring this up to her without making myself sound like I'm trying to control her or that I don't trust her.
<bot>: Girlfriend has history of cheating on her only major ex-boyfriend.  She admits it was a mistake, but blames her ex for her actions instead of herself, makes me worry about our future.