So, work out what's really causing the issues. Is it really that everyone has failed your trust or is it that you don't think they should trust you and therefore everyone is like you and will go on to cheat?

If you have more self confidence then it won't be an issue.

Its just you're ego fucking with you, it tends to happen that if you percieve someone as a threat and your girl see's this you will make this person a threat. If she see's you are wound up and annoyed by it then she will start to think and you will push her away. Act like you don't give a shit infront of her, even if you are dying inside. Keep the cool