You keep mentioning gifts...gifts don't prove ones love for another person,sure they're nice gestures but not much more.They don't seal the deal or anything.

This is your issue,not hers at all.What she did before she got with you is really none of your business.

If you can't let it go,you should seek out professional help if you plan on staying together because it definitely will not work if you are going to hold it against her.

Were you in any sexual relationships before you met her?