I agree with Mono's statements in terms of asking yourself what your goals are. It's hard to do when you are in love and thinking in the moment and usually goals would not be an issue, but it might help you clarify what is worth pursuing. You are in for a long haul if you decide to keep at it and love two that don't get along.
Does the new love tolerate your girlfriend?
I suggest doing some reading on some of the blogs. There are some interesting dilemmas around which you speak.
here are two suggestions.