I can't count the red flags, but he really sounds more like a cowboy. Talking at only two months about how he is better for you than your husband?? I wouldn't want that talk. I expect everyone loving me to at the very least respect the others in my life! No one is replacing anyone and if he doesn't get that, then he's not going to get poly.
The VERY SERIOUS discussion of safe sex and children is one that everyone should have had, and agreed upon. While my bf jokes about having kids with me, he jokes now because he knows that it's taken care of, that we won't be. He'll have kids, and he jokes more now about how I shall spoil them! But, he doesn't want to step into those shoes, I have kids, they have a father, that's not his role.
Your boyfriend doesn't want to 'share' you, he wants to rescue you. If he thinks that's what you need there's two ways I'd handle it.
1) look and see if you need rescuing. If you do, then rescue yourself!
2) look and see if you need rescuing, if you don't, then he needs to back off!
Some people need to feel like the hero, the victim, rescuer, villain triangle. Not your job to break him out of that, his job.
Me: Late 30s pansexual poly.
DH: My husband of 19 yrs and father of 3 teen girls.
DC: LDR of +4 year