I take it you are looking for a triad? or is it a vee... cause if its a vee then isn't it up to him who he picks? Maybe that would be a better option if you don't like his choices.
the other thing is; and this is what I have noticed in my life... my husband picks women who are just like me!!!!
freaky! And really difficult because I have had to face my shit. Most of them are so much like me they want to be the center of attention and don't like that they are in our relationship together. Other than that they have no poly skills and don't match up as we have 12 years of experience. Not to say we are super stars, but damn near it
heh, just kidding. No we have our moments, but we at least no what our foundation is.
I suggest starting with figuring out what your goals are and if they are reasonable. maybe it's time to let a few boundaries go and let it fly a bit more... "rules" are not workable... boundaries mean that there is breathing room as they are fluid... start negotiating what they are and give each other some freedom.
Lastly, do some reading on here of other threads... check the stickies, do a tag search for "unicorn" "dating" anything that takes your fancy. It sound like you have some hard work to do to make it work for you. You have gone the first steps already, time to figure out what the block is and get rid of it so you can move on... some introspection and educating might go a long way.