I think it's quite a patronising generalisation to say that all guys have a innate need for sex which they cannot control. I'm expecting to get a few jokes for this, but I actually think many/most men (including young men) have priorities ahead of sex. Having a good relationship with a loving partner just one of these.
Men may enjoy sex but they're not sex vampires, requiring constant doses to remain alive or happy, as is the myth. Besides which, the need for sexual stimulation and release is one that any man can at least learn to achieve, all by himself.
So no, I'm not going to allow my boyfriend to have sex with others, not least because I don't want to acquire disease or for him to have a child with someone else - but because also such infidelity would make me sad, and undermine the exclusivity of intimacy (sexual and emotional) that sort of defines our relationship. He wouldn't want me to have sex outside of the relationship, so I very much expect he understands and values the reciprocal feeling I have.
That said - other people define their relationships differently, and I'm not one to judge an open, swinging, or polyamorous set up if it suits others. But please - on the grounds of mutual "coolness with that", not because men can't help themselves and women have to compromise their feelings and values or be forever alone.