I get what you're saying about moving at the pace of the slower person, there are just some troubling things here. I do think he needs to come here, get some perspective, and explain what the heck is going on. It's not ok to keep threatening your relationship ("I'll leave if you can't give me this! I'll leave if you need this!") and acting in ways that make you feel unvalued (doesn't want you to be poly but is actively entertaining potential new partners). Maybe seeing it all laid out and getting the chance to explain himself will help break some of these patterns before resentment builds up that could really damage your partnership.
The major players. Me, 30ish bi female. Gia, girlfriend of 4+ years. Clay, boyfriend/dom. Davis, ex/friend/"it's complicated." Eddie, roommate & fwb.
The supporting cast. Eric, Gia's husband. Bee, Gia and Eric's toddler. Dexter, Gia's lover. Helen, Eric's lover. Izzy and Nikki, Clay's partners. Liam, Eddie's husband.