You sound like a great person. I agree with Perna on this - she needs to deal with this on her own with a therapist. You shouldn't have to be worried about going out with your buds/talking to women at work and her reaction. You shouldn't have to pay the price of her past partner's infidelity. She needs to accept that you're trust worthy and your freedom shouldn't be restrained in any way. If she's being triggered this shouldn't alter the way she treats you or the way you conduct your life. Best of luck.