with everything in life you take a chance. only each partner will know when its right to take that chance, and that will be when you ultimately trust each other. anytime before that and you are taking a calculated risk.
but in any case, for those that believe you should always protect yourself in a committed relationship, i respect your opinion, but to me that only works in the beginning of that committed relationship, as you are still getting to know each other, build trust and more importantly nourishing the love between the two.
But once you pass that stage, if you still believe in wrapping it up, then how does that make your relationship committed? if you cant trust the one you love, who can you? I'm not naive, i know there it happens. it happens al teh time. there are many who can mislead and cheat us, and blame it on "weakness", being influenced, and other bull shit excuses. but that is why we need to look for the right guy. usually they are the ones that are not perfect, the ones who are single, but we still manage to overlook.
i can't honestly love someone, give them my heart, and look forward to spending the rest of my days with him, if i cant trust him. that relationship is doomed to fail if either of us don't believe or trust in each other. the only thing one can wish for is that if one of the two dare to cross the line to the dark side, then have the decency of wrapping it up and protect your own life and the one you say you love.
and hell if you are weak, horny, hot for someone -- your committed relationship should be reason enough to communicate that to your partner.
i will give my partner the benefit of doubt, because if i am with someone, the right one, it is because i truly love and trust him. i want him to love and trust me the same.