Know you aren't alone, this is exactly how I became openly poly with my husband. Only recently he seems to be trying to express an interest in my physically, which is a surprise. I have no secondaries or even any interest. I kid a lot about different possibilities but honestly I have been too busy with my different interests in life to really find someone again.
I will tell you when I told him about the DADT and falling in love with someone he said he was scared that I would just leave him outright. At some point I was tired of feeling resentful and many of the things you are going through.
You know something really strange... years of asking and cajoling about (not) being physical, he has given me some attention lately as I mentioned and emotionally it hurts because I have felt resentful about it for so long... so now I am figuring out what to do with that feeling... I haven't rushed back into getting physical with him just because he is expressing an interest. Also this will sound dumb, but I wondered if truly wants me or just doing because he knows it is what I want... if that makes any sense at all...?
Oh friend, I hope that you can sort it out. You aren't alone for sure.