history: I have been faithful to my long time girlfriend. I would never cheat on her I have a girlfriend_comma_ and I would never cheat on her That is an amazing thing. Being cheated on is one of the worst things that can happen when ones enters a bond like a relationship.
current: I agree, I am not sure how people can do that to each other
next: I am sure that you two will have a happy and loving life together especially if she reciprocates your desire to never cheat. 