Does he want to be co-primary with your husband, or is he ok with being a secondary partner while living under the same roof as your primary partner? If the latter, that seems like it could be a very taxing situation for him, emotionally.
Why do YOU want him to move in -- just to comfort him, or because you think you guys are really at that stage on your relationship?
Is there a Plan B if living together doesn't work out, would he be financially able to move back out and get a place on his own?
Am I right in thinking you have another bf? What does he think of this potential development?
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.