Hey Kristina, it's good to hear that you're doing well.

I can understand how annoying this is for you. You sound like you just want to live your life, so what gives?
Your ex probably feels that his attachment to you is fading. These are his efforts to restore it. Have you considered not reacting when you see him, or perhaps filing a restraining order?
His current girlfriend probably wants to meet you because she feels threatened by your presence. I'd consider her reaction pretty normal. He's acting quite oddly around you and maybe she thinks something's up. She probably wants to get a better grasp on who you are as a person to determine how she actually feels about his actions. You are not responsible for soothing her insecurities, though. He is likely attempting to triangulate you with her and himself because he has begun to devalue her. Things must not be going so well for them.
Either way, what you're doing appears to be working for you. Keep at it and do whatever you feel is necessary to protect yourself.