"If I need to omit certain truths to my gf to see you I will"
How would you ever trust someone that would say that behind his girlfriends back? Someone like him, a person with no personal boundaries, isn't going to make a good lifemate to anyone. You? You're headed down the same "shitty relationship material" title because you yourself have no personal boundaries. Change that up and hone those personal boundaries so that you don't find yourself falling for men that keep their girlfriends but lie to them.
Notice that statement doesn't say ANYTHING about ditching her to be with you. It's a loud and clear statement telling you that he keeps her while you remain the "dirty little secret." Blech and patooooey! Why would you want to settle for that kind of man. EVEN IF HE LEFT her?
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion