Protect yourself and your partner
So he says he's always been faithful? It means ab-so-lute-ly nothing. You made the same promise to your partner too, remember? You can't prove he's telling the truth, so don't take any risks: always use a condom and make him take an HIV test with you. He could give you and your partner STDs or worse. Your affair might seem like a bit of fun but it can be a very, very dangerous game if you don't take the right precautions.
Protect you and your partner from him
So he's gorgeous, caring, sweet, and he'd never do anything to hurt you? Rubbish! You just never know. Just by being with you, he's an accomplice to your lies and he could easily betray you. What if he got angry, jealous and posessive? What if you end it, he can't stand being dumped and he decides to tell your partner everything? Think ahead and make sure he has no hold over you. Don't tell him where your husband works and don't give him your address or home number (you can always blacklist him on your mobile or change your number).