Generally speaking, men cheat because they have the opportunity. That doesn’t mean that a guy will definitely cheat just because he has the chance, but rather that availability of a ready and willing partner is the primary motivator in moving men toward infidelity. And they may be unfaithful, even if they are perfectly content in their relationship with their significant other. In other words, their cheating is not reflective of how they feel about you. It simply indicates their unwillingness to exercise a little discipline and resist temptation – no matter how into you they may be. I repeat, they may cheat even if they are incredibly happy in their relationship with you and you have an incredible sex life. It is not a failing on your part or indication that there is something fundamentally wrong in your relationship. It has to do with the fact that monogamy is counter-intuitive for men, and therefore committing to have sex forever-after with one woman and only one woman is a challenge. And that challenge is one that many men are just not up to.
So what can you do to absolutely insure your guy won’t stray? Precious little. There is no product warranty on guys. His fidelity is based on his ability to embrace monogamy, no matter how unnatural it may seem to him. If he wins that battle, you have a faithful partner. It’s as simple as that.
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That being said, not all men are equal in the potential-for-cheating department. Guys tend to fall into one of three groups: 1) Those who are open to the possibility, itching to cheat, or actively pursuing “extracurricular activity”; 2) Those who like to think they wouldn’t cheat, but who can and do succumb when opportunity knocks (by far, the largest group); and 3) Those who have the discipline to resist temptation…even when opportunity is present. For this group, remaining faithful is a matter of honor. Betraying you would be betraying themselves, and they will avoid doing that at almost any cost.