We've gone thru different phases in our past 10months of poly. At first our married sex life was vamped up by my having sex with my bf. Then my husband got upset, and we went about 2 months where he said, "as long as you're having sex with him, I can't have sex with you." That worked for a short while, but eventually it actually made me incredibly horny for my husband! He suddenly became the "forbidden fruit," and I was wild with desire for him. He finally gave in
Was your sex life going well before the bf came along? I mean, not just for you, but for her as well -- have you asked her? Maybe there are some different techniques you could try. At this point, respecting her funk and not pushing her for sex is a loving thing to do, but you can still be physically affectionate, and maybe she will warm to your gentle touch. I think a lot of guys forget that women are different, that our sexual needs are not the same.
It sounds like you have a lot of love in your relationship, so hopefully you can communicate your way through some of the sex issues. It's weird when you're married and you get so close, the intimacy can get like brother and sister, best friend love, instead of the erotic, sexy love. You can have both, it just goes thru phases, I think. But you are a sexual male and you are married -- you should not have to go without sexual intimacy for too much longer. IMO, patience is one thing, but celibacy in marriage is not really fair to you, if you still feel the desire. Especially after only 3 years of marriage, but even the longest-standing marriages can get the fire back, as long as there's still a spark...
Welcome to the forum.