If you are in a relationship,a true relationship you should not bring up her past. You should get it very clear that it can be painful. If the answers of questions u have been wondering about like :
How many people she’ve slept with?
How many times she’ve been in love?
... etc were not only in 1's & 2's but more than that it can really be a heartbreak warfare.
So just try to be positive. Remove these thoughts from your mind and find ways to live a happy and peaceful life with her.
RE: "How can I ease agonizing thoughts about my girlfriend’s past relationships?"