how do deal with when I am so horny and my guy isn't interested

I want it like everyday but he fine with 1x/week sometimes 2x/week, we talked about it and he said his back hurts, he does have back problems but I feel very hurtful when he is rejecting me, but on the other hand we love each other very much. We have been together for 13 years and have 3 beautiful children.  What do you guys think? What should I do ? Thanks in advance