Hasbian Helper
A lot of straight broads won't go the threesome route for various assorted reasons (they don't like to share, aren't into dining downtown, etc.). And while having a big gay past doesn't necessarily mean you're any more likely to invite another lady into the sack with your newly beloved, that's what's going to pop into most men's minds upon hearing the news you've tasted twat. And once that idea pops in, good luck popping it back out. Prepare to be pestered.
Which is why you shouldn't be running around telling every frat boy who crosses your sheets. Wait till you meet someone who looks like a long-term possibility. It's not a disclosure along the lines of an STD that demands you tell prior to full-frontal, nor is it something that is so shocking you need to turn it into a big deal.
Unless. . . you mention that you've had a change in "values," and that makes me a tad queasy. You're not one of those creepy scripture-quoting graduates of Camp God-Only-Likes-Straight-Peeps, are you? I sure hope you weren't brainwashed into thinking lesbianism is some sort of aberration or crime against humanity. Uh, because it's not and the hatemongers who run organizations like "the International Healing Foundation" (a misnomer if ever there was one), and purport to "cure" homosexuality are noxious and evil and I can't even believe we live in a world where this is an issue. Then again, god created Adam and Eve, not Adam and Steve and the laughably misnamed "intelligent design" is finding its way into classrooms.
Ahem. But that's probably not the case with you, now is it? For the sake of keeping my lunch down, we're going to assume you're just someone who-like a lot of people (especially of the female variety)-has a sort of fluid sexual identity and leave it at that. Which brings us back around to your question. Please don't sweat explaining your dating history, because hey, welcome to dating the hairier sex; unlike us ladies, who like to painstakingly dissect situations and analyze not only our feelings, but from whence these emotions stem; men don't really give a shit. They're a lot easier-going (i.e. oblivious) than us. Throw in a few gender-neutral pronouns (e.g., "my ex," and "they" spring to mind), announce you're one year out of a five-year relationship and he'll be none the wiser and you can wait and see whether or not to bother giving him the full scoop. Bear in mind that most dudes only hear, on average, about half of what comes out of your mouth (that's being generous), and if you can keep yourself from having a sputtering red-faced spazz-attack, you'll be fine. I can almost guarantee he won't press the issue because first of all, nobody really wants to hear about those who've come before them, and second, he probably didn't register your answer anyway. And yes, you may think Mr. Hotty McPecsosteel is listening to you because he'll give a head tilt and offer the occasional "really?" but the fact is, he's busy looking at your boobies.