I also get that way when I'm on my period. I have way more fantasies and want to masturbate, but it hurts to do that plus i dont like getting blood on me. When I'm in a relationship, even though i'm horny, I dont like to have sex while i'm on my period. I mean, if its not that heavy, like the last couple of days, i will. But maybe you could please your husband in a different way, like through oral sex. As for him pleasing you, he could just stimulate your breasts. That might be good enough. And he would enjoy it as well.
Now, about the part about that being a sin: that was written in the old testament. Things changed after Christ came. In the old testament, you had to do certain things to be considered "clean" in order to have a relationship with God. Those things are no longer necessary to have a relationship with Him. However, if you are Jewish, you only believe in the old testament. So if you are Jewish, and if you feel that it is a sin, then refrain from it. The Bible says that even for those who believe in the new testament teachings, that if someone believes something is a sin for them, then they should not do it.