Should I stay or should I leave?

I met this guy in 2007 and we dated briefly before being torn apart by misinformation. We reconnected in 2024. He came with a lot of baggage from a recent 10-year relationship break-up. He has been honest with me, and we started dating again while I'm going through a divorce. He wanted to move out of the country, and I got him a job where I am. Just as he was about to leave, his ex contacted him. Though she is dating someone else and says she is happy, she constantly wants to stay in touch with him. He has always been polyamorous but was willing to be monogamous for her. He has had many sleepovers at women's places, yet he insists nothing happened. When he's out with friends, he often forgets his phone and seems to forget I exist. Now he and his ex have started meeting again. Though she doesn’t want to give him another chance, they keep talking, texting, and video calling. He says he will never love or feel for anyone like he does for her and will never move on from her. I have been in love with him since 2007 but am so confused about what to do. I want to give him the world, and he doesn’t want to hurt me. I'm confused about what the right choice is. Should I stay or should I leave?