Get a new boyfriend. Since you have no children together the break out will be easy. The work you will have to put into this to get it to work the way you want sexually will take years if at all. Combine that with the physical pain he has and wont do the surgery to correct it means this is just a dead end street. 18 months is a long time.

I've been on the reverse side of this and after a while you will just become resentful, hurt, rejected and feel inadequate.

Get your house in order and go looking.

Cheers
JDS