<human>: Question up front: I'm looking for words of wisdom or perspective altering advice for dealing with a girlfriends past. 

Story time: My girlfriend of 5 months and I were getting ready for bed last night and we start talking about her ex-husband, which I knew about. Nothing really new of note there, but we somehow got started on the topic of what happened after the marriage ended and what happened before I came into the picture relationship wise. Bad idea, but my curiosity got the better of me at that moment in time. 

Nothing really threw me off, some randoms here and there, except from January-April of this year she was fuck-buddies with this doctor in his 40s. Stories about him taking her on trips to exotic lands followed, that unsettling feeling where you're trying to hide your anguish and not knowing if you're doing a good job soon followed. 

Now, I'm sure that's standard fare for a decent number people about to hit 30 to have that sort of past at some point in their life story, but it has me totally mind fucked, how could I live up to that? 

Am I comparing myself to those that have come before me to the extreme? After falling asleep with it on my mind and thinking about it throughout the day. I don't want to let this affect how I feel about this girl. I know she's with me now and the past is in the past, but I can't shake this feeling that I can't live up to the time and experiences she had with this guy basically right before we started dating.

Condense the text into a few key points
<bot>: Discussion about her exploits before me has rustled my jimmies. What can I tell myself that could put this type of comparison to past lovers into perspective. Thanks in advance for any replies.