My two pence worth, may get a bit graphic but I'll try and keep it as tasteful as possible.
After I split I had an itch that needed scratching and found a willing companion or two on fab. Now, a few reasons why chose a couple. One, couldn't pull a single female, two was worried about falling madly in love with the next lady who undressed in front of me there and then, three, with a couple, the man there would assure me it wasn't going any further, sex with him and the wife, good time for all. Anyway we hit it off and have had a few sessions however on one occasion things went a bit further than I hoped.
I was receiving oral from her while he was taking her from behind, we were led on my bed, he then re positioned himself to lie on her and kiss her neck while still in her, she still doing her thang on me, he then went to take over from her and I freaked and froze and that was pretty much that.
Apologies were soon offered and accepted but I was definitely uncomfortable with that scenario, now plenty of people would have liked that, it wasn't for me, the sex with another couple was usually good, we got on well and respected everyone's boundaries up-to and from thereon (we have met since) but I know after that I definitely am straight.
However. In the last year I have experimented with prostate play, I have a few things to assist and have in the past had sex while wearing a prostate massager but, I don't want to be penetrated or pegged, again I don't have a problem with anyone doing that if that's what they want and it's all consented to but several years ago I probably wouldn't have even entertained the idea. The same as I probably wouldn't have felt comfortable being nude and erect in the presence of another male several years ago. People do change and weather you identify now as straight, gay, bi, pan or just active to me, doesn't mean you will be forever. Experience counts for a lot imo and, I don't think trying new things makes you x, y, or z but continuing to indulge in these specific acts will or would.
Just my thoughts hope it makes sense.