If You Get Caught

Deny, Deny, Deny

Never admit to anything. Deny everything. Unless you're caught in the act of having intercourse, deny, deny, deny. Most people are more than happy to live in a state of denial; your significant other would rather believe you than admit to herself the terrible truth. So deny as much as is plausible, and then some. 

Never Confess to More

Even if you're caught in the act, never confess to more. If she catches you kissing another woman, say you've never done anything besides kiss. If she overhears a telephone conversation, never admit to anything beyond flirting. If a third party sees you together with your lover, say you're simply friends, or deny you were ever there. Whatever you say, never confess to more. She will grill you, pester you, interrogate you until you break. But don't give in. Never ever confess to anything.

Only One Time

Never admit to doing it more than that one time you got caught. That one time, that's the only time you ever did it. Stick to that story to the end. Never admit to additional women, never admit to anything. Simply say you made a mistake, it was a one time thing, and will never happen again. She will try to trick you into confessing to experiences with other women, but you must be wary and stay strong.