My girlfriend and I are on a break for six months. We're allowed to do whatever we want with whomever we want. Last week I engaged in oral sex with a friend of mine. My girlfriend is visiting me next week and we plan on taking a break from our break. We may possibly have sex: oral, vaginal, or both. When we were dating full time we both got tested and did not use any form of protection besides birth control. We were both STI-free and monogamous. I feel inclined to tell her about my oral sex encounter just so I disclose any possible risks to her. Should I not tell her about my oral sex encounter and just have fun with her? I don't want to hurt her (by telling her) but we did agree that we could see other people during our break. If my GF and I do get intimate, I plan on asking her if we need to used protection, i.e. if she's been with anyone in the interim that would put me at risk. If she has, I plan on using a condom. Should I tell her about my encounter or is it not enough of a risk to mention it?
Oral Sex On Break
My response after the jump...
Each of you should assume the other has fucked around.
You took this break, after all, expressly so you could do "whatever [you] want with whomever [you] want." You've already done what you wanted to one person you wanted and your girlfriend has most likely done the same. Now to avoid emotionally tricky disclosures about what you've both been up to—or down on—during your break so far, OSOB, you should simply default to using condoms with each other for the duration.
Say something like this to your girlfriend: "While we're on our break, honey, we should use condoms with each other. Once we're exclusive again we'll both get tested and then, once we get the all-clear, we can go back to condom-free fucking."
It's really the only way to avoid putting each other at risk. You're tempted to hide your one encounter from her to spare her feelings—which already has you contemplating putting her at risk—and it stand to reason that your girlfriend may be tempted to do the same to spare your feelings. Or what if you disclose your one measly encounter and your girlfriend freaks because she's already fucked the shit out of ten randos? She might panic and claim not to have been with anyone and then feel like she can't turn around and insist you use a condom—she can't protect you—because then you would realize she had lied to you.
You can avoid all of that by simply agreeing to use condoms during this break-from-your-break, OSOB, and any subsequent breaks-from-your-break.