<human>: Can you give me a shortened version of the text?

I've been dating my gf for 6 months now.
The other day she left her laptop open on my desk and I sat down and saw her Facebook was up. She was in the shower so I (naturally being curious) checked her messages. I KNOW IT'S WRONG BUT WHATEVER.
I searched faaaar back and read conversations with her friends when she was still with her ex (a year ago). Half of the conversations were about praising her sex life with him. Apparently they usually had sex twice a day for at least the beginning of their relationship. She claimed that she just wanted to fuck him all the time. She claimed he was the best boyfriend ever and she's the happiest she's ever been. (More context: They broke up on good terms later and still hung out all the time.)
Here's my problem: This never happened with me. We've been together for 6 months now and we've only had sex twice in a day ONE time and it was on a vacation. I have to push her for sex all the time and she doesn't seem that into it. She claims that she loves me, the sex is good, and says that I've been the best bf she's ever had but knowing what I now know has put a gigantic damper on my mind set with her. I can't tell if she's lying or not.
I feel undesired. I feel like a shitty boyfriend. I feel like I want to die.
So I guess I just don't know what to do. How should I approach this situation?
<bot>: Read gf's old facebook messages. Saw she was more into her ex's sex. Don't know how to handle it.