Ok, so everyone is basically against it and I didn't read all the way down because there are too many but I read most of the responses and while they are mostly in agreement, none are really telling you HOW to do this. Often if you tell yourself not to think of someone, you'll think of him more. Like saying, "Don't think of the pink elephant" and what pops into your head first is a pink elephant... SO, my suggestion is that every time you smell a horrible, bad, putrid smell (like when you poop or puke), think of that man. Don't laugh! Ok laugh but it can really help fight the urge. Instead think of something else that can save your marriage. Think of how sexy your husband is. Put those two suggestions together and you have a powerful plan. Other man = puke with poop in it. Your husband = chocolate, caramel, vanilla. Do this with every sensory power you have in your body. Sight ... find an ugly, grotesque something about the other guy and look at it each time you see him, maybe he has foot fungus or imagine he does. Always let your eyes linger on your husband's 6-pack abs, firm rear, or intense eyes. Remember that other man's belch, it's sound and smell and be disgusted by it. Remember your husbands sweet, comforting voice as he whispers "I love you." You get the idea.
Also realize how disgusting it is that he would betray his best friend (if he'd betray a best friend, he'd betray a girlfriend or wife because often spouses are best friends too) and focus on the horrid aspects of his actions.
Some of my husband's friends were very flattering and charismatic but what I also noticed is that they were players ...they used women and that disgusted me so I let myself be disgusted by it. It's ok to think bad thoughts about men who are not your husband. Don't be nice all the time. It's OK to judge someone harshly who's acting inappropriately and hurting people. And soon I was disgusted when they'd try to play me.
One, his cousin, actually made a play for me and although I was attracted to him, I stopped him because I loved my husband more than that flattery I felt and I said as much to him and said, "I thought you loved my husband too. I'm very hurt and angry." I told my husband everything including my attraction to his cousin. This was before kids. He didn't get mad or anything. He just said, "I love you so much. I would be hurt but if you need to go find out if you love him more, then that door is open ... go. I want you to be happy even if it means I'm heart broken. But just know that if this bed is filled with another woman when you get back, you won't be able to come back." I knew in that instance my husband was the better man and 18 years later we're still together and still faithful. It's my choice to stay and find a way to work it out.
Because of something from my childhood, I have issues in this area (concerning love and self love) and occasionally am attracted to a male friend but I keep them at arms-length and because of my issues and because of my husband being a musician (let's face it, they look 10 times cuter when they're on stage), my husband and I have come up with 5 rules never to cross with another person. If one is crossed it means we have big problems we need to discuss and go to therapy about to regain the trust immediately ... before any others are crossed.
Shortly after setting them up, we each had a slight oops and then we did our plan and it worked to resolve the issues and we haven't had any oops since. You'll have to come up with your own but ours are things like: No cuddling all night with someone other than your spouse for any reason ... I don't care if she's crying all night, you don't stay over there, you come home ... if she's suicidal you call a therapist for her and come home or you check her into a hospital and come home or you call me and I'll stay over night with her with you.
Others are: No open mouthed kisses. No anything stuck into any orofice for any reason (other than GYN appointments or ear infections at doctors offices of course). No nudity (meaning no privates exposed not even for Mardi Gras). ... stuff like that. You get the picture. Any temptation of these things and we talk first before anything get's to that point.
And try the bad smells imprinting thing. Seriously! Marriage is a choice. Choose the right guy ... the guy you married is the right guy because you already chose him. (Unless he's abusive. Then run and seek therapy before starting any other relationships because you'll need healing first.)
By the way, my husband never confronted his cousin but they are now estranged because of another betrayal having to do with music. If a man would betray his best friend over one issue, he'll do it over another, and I love my husband ... how dare someone try that on him. It's despicable. Focus on all the ways that other man is showing you he is a creep, be polite if you must for your husband's sake, but notice the other guy's creepy, smelly side.
Not to mention all that hurt others have pointed out this man could inflict on your kids. Protect yourself, your husband, and your kids from him. Don't let him take advantage of you. You have a lot to lose. And yes, do give yourself love in other areas ... like with your husband ... so you are strong enough to resist another's false promises. Good luck!