Most Helpful Guy
I doubt she was messaging you too when he texted you, typical excuse a guy would use to talk to you. Obviously he is still into you otherwise he would not get mad or keep texting you, but he sounds like a big time loser who can't handle rejection of any kind, sounds a lot like my ex. Broke up with me outta the blue then wants to talk, i told her i had a hang over and maybe later. Got hella pissed saying i never drank when we were together, blah blah. Ex's are weird when they realize they dont have a hold on you anymore.
Most Helpful Girl
It sounds to me like your ex is not over you, and his new girlfriend knows that. Her trying to insert herself further into your life than she was before seems like an insecurity to me. Also, if you were friends before and there hasn't been a conversation of "I don't want to be your friend anymore because you betrayed me.", maybe you should clue her in. As for him, his unresolved issues MAY be because he still has feelings for you, but they may also just be because he wants YOU to still have feelings for HIM. It's hard to tell sometimes if someone is nurturing their heart, or their own ego. You know him better than I do so I would trust your own judgment on that. Regardless I would calmly, soberly, make it clear to both your ex and his new girlfriend that you aren't interested in maintaining a friendship and you hope they can respect that. It sounds to me like they don't realize that line of communication is closed for you.