ok, #1 go to him, hang out with, and just flat out tell him you guys should hang out more often. Make sure he's still interested. If there's no interest in the beginning truth is there will probably never be any. I'm not trying to be harsh, just brutally honest. #2 That other girl he probably just considers as a friend so don't blame him, but she might consider it as an opportunity so you gotta make it clear that he can hang out with you but that his main woman priority is you. #3 Don't worry so much, chill-ax if he's with the girl you gotta learn to trust him, next time you see him don't harass him... like what have youbeen doing with that girl, that would just piss him off. Trust is the foundation of every relationship.
Don't worry, Be happy. Remember, Living is laughing, laughing is loving, but loving is a gift. :)