I would love to post the whole thing here, but it's a lot more than 2000 characters, so if anyone is interested in my story and might shed some light, please feel free to read it here (reddit).
Most Helpful Girl
I'm going to assume her boyfriend basically followed you two on the date because I don't want to read.
If so, I would ask her about him and tell her that that's just creepy. It seems like he likes her due to his behavior or is very protective, but that's not going to get him noticed faster.0
Most Helpful Guy
Both of you sit him down and tell him you are concerned about him and his behavior. Tell him that he and even you will never own/posess a woman/person and he should seek help from someone that cares and is capable.1