My first instinct was to break up with him, but he came forward with a robust plan I didn't expect - and in a week he has gone to therapy, decided to not go out until I can trust him again, and to change his life even when I do trust him again so he is not ever in a risky situation. The biggest plan is to practice 100 percent honesty with me.
He says this change is not all about me; he feels he is ready to change himself whether I stay with him or not. He is 27. Am I wasting my time by giving him a second chance?
Answer: It's funny - we tend to give people more credit for saying the wrong thing, because at least we're sure they mean it.
It is, of course, a valid question, and if you decide to take him at his word, then you'll need to keep your mind open to any possible outcome, including one where you discover he manipulated you from beginning to end.
If that sounds more like living in suspense than being part of a trusting relationship, then think of it this way: No matter what he promises, no matter how plausible, the sensible approach remains the same. Live each day, be receptive to truth, make choices accordingly.
This is not to suggest that you scrutinize every detail of the past, present, and future; that's just misery. Instead, my advice is to discard whatever narrative you're tempted to superimpose on yourself, your boyfriend, and your relationship, and just live by the reality you have in hand.
That means recognizing that your partner is a temptation-wrestler or birthday-forgetter or stress-eater or emotion-bottler or whatever other trait just isn't going away, no matter how much better life would be if it did.
And it means choosing to stay with someone only if you can see these things as the price of a life that suits you well, not as temporary obstacles to some imaginary better life.
With this guy: Cheating is a real possibility. Can you accept that when it happens? Enough to quell the nagging fear? "Not ever in a risky situation" = delusion.
Please accept that anyone can cheat on anyone - and so what matters is whether you're in a relationship worth the risk things that will go wrong in ways foreseeable and otherwise: cheating, infirmity, unemployment, sick child, unforeseen conflict, whatever.
And please also look inward, to see why you keep assuming high risk despite a low tolerance for it.
I can hear the "Once a cheater, always a cheater" crowd screaming for me to shut up, and it's often that simple. But are you comfortable with fidelity as the variable that counts the most?
E-mail Carolyn at tellme@washpost.com, follow her on Facebook at www.facebook.com/carolyn.hax or chat with her online at noon each Friday at www.washingtonpost.com.