Wow. I saw your post from the other day that mentioned breaking up after 3 1/2 years and I was considering asking you what happened...
That's pretty major. Sounds like his new girlfriend is a crazy control-freak psycho bitch. I'm guessing the scenario from his POV is... still in love with you, so goes and gets a rebound girlfriend, who likes him more than he likes her and suspects/realises this, so decides to go whacko and entrap him into an engagement (I guess he's pretty emotionally vulnerable atm - easy to play off for her) and cut you out of his life to keep their relationship "safe".
Hopefully he'll get out of it himself before he realises the mistake he's made, but that's no reason for you to stop trying to contact him, especially since he said he wanted to meet you again and speak to you about a problem with his girlfriend. If these other friends have ways to contact him, could you get them off him? (And maybe meeting up with those friends had something to do with him asking for advice about you?)