I'm so grateful you brought this up.
I do hope to hear how it went, hope you'll come back and let us know.
My situation is a bit different, but I share the nerves. I have two boyfriends. I dated First BF 8 (9?) years ago, for about two years. He met Current BF and they became friends back then; then the three of us were good friends. I broke up with First BF, and Current BF talked us both through it. Then Current BF and I started dating, after a year moved in together. The three of us continued as good friends. We lived together five years (longer than I had previously lived with anyone). I asked him to move last spring, and it was a breakup (though First BF commented that it was the most insincere breakup he'd ever witnessed). I think details are in my blog, but now I'm seeing both of them (since December).
I don't think they've spoken (but I'm not sure) since this started. I know the three of us have not been together since this started. First BF is about 3 hours away, so that's not unusual for us. I'm very nervous about the three of us being together. I would hate for this to spoil our friendship, it's very precious. It feels like an emotional triad to me. They are both not spectacular emotional communicators.
When Current BF and I lived together, and First BF would come to visit, I was 'cuddly' with him. I would stroke his hair (ghods, he has fabulous hair), or have extra hugs, or whatever. I knew the Current BF was secure and didn't mind. However, Current BF and I limited our PDAs in front of First BF, because he was slightly uncomfortable with it. He had a limit to my expressions of affection to. Current BF and I cannot be in the same room without touching ~ what we do best is snuggling. He leans into my touch, always. First BF is only open to it when he's open to it, and I'm not always able to tell ~ so sometime he's flinched, and then I'm sad ~ it's hard to touch somebody who flinches. So, now that I'm seeing both of them, I'm nervous about how that will go.
We don't have any plans to hang out together anytime soon, but I know it will arrive eventually. I'm trying to learn to move more slowly, and be okay. Perhaps it's more 'moving at the pace of the most uncomfortable' (what's that called? that's not right) ~ it's not that they're uncomfortable so much, but they move glacially, relationship-wise, and I speed-skate. *sigh*