<human>: Can you succinctly summarize the text in 1-3 sentences?

Husband and I have been together 9 years, married 3. He is my best friend in every way, and we have a really great marriage. I do have a much higher sex drive than he does, but I knew this going in and it doesn't usually cause major problems.

I have known his best friend the same amount of time as my husband. Ever since I met him, I have been attracted to him sexually. Lately, it seems the attraction has multiplied by 100. I think it is mutual (I have about an 80% certainty if I had to put a number on it).  I fantasize about him a lot, especially when I masturbate. I get excited when I find out we are hanging out with him. I feel a really strange sense of jealousy towards his girlfriend (why do I care??  I'm married!). I don't think my husband knows. 

I love my husband and I will not cheat on him. His best friend and I are also good friends, but I will not ever let myself be alone with him. I don't want to feel like this. Nothing will ever happen, but the attraction is incredibly intense. Does anyone have any advice as to how I can deal with this?  As he is my husbands best friend, cutting him out of my life is not an option.
<bot>: Extremely attracted to husbands best friend, and I believe it's mutual. I don't want to be. Any advice?