If you are living/sleeping together, that goes beyond "just friends" to me.
So his agreement with you is "be in a serious relationship with me, make sacrifices for me, (but don't say you love me) until someone who can bear my children comes along" ?
I have never met the guy, obviously, but this just feels so wrong to me. I wish you luck on your journey. I would get out of that relationship, or non-relationship, whatever you all call it. (confused?)
Bisexual, Hinge of a Vee with a mono boyfriend and poly husband.