Get rid of him, quickly. He's not committed enough for an LDR, and you will end up becoming very affected by his actions to the point where your confidence is shattered. If you are going to last in an LDR complete trust, communication and most importantly commitment is required. From what you have described he clearly is not able to contain himself.
Also, the girl, if he has shared that much that it is awkward, then he is clearly untrustworthy.
I'm sorry to say it though, but he just isn't right for you in this situation.