You're his stand by girl. If anything goes wrong with his girlfriend, he knows you are waiting in the wings. Is that what you want, to be someone's emergency plan?

There are tons of guys out there that will put you first, you deserve nothing less. Say goodbye to this guy, he's not worth it.

Good luck.

The answer is easy -MOVE ON!! You deserve so much better for yourself, and not to be involved in anything messy. Seriously, the girl probably had it plotted out, she got jealous he went back to you and made her move. The fact that he went back to her after he wanted you back, obviously is a sure sign he doesn't love you as much as you think. Love hurts. It's reality though - watch sex and the city and you will feel much better :-) good luck

He doesn't love you or the other girl.

In fact, his actions justify his thinking. Clearly, he needs to a fMRI scan to see what's going on with his brain. He chose you, then left for the other girl.. then came back.. now left you again.

Do you see a pattern? He is unstable in relationships. Time to find a new, nice guy :D