what got my bi side started and the time between encounters

When I was younger (17 or so) 4 or 5 close buddies of mine use to hang out at this little restaurant, sort of like the show Happy Days and Arnold's Diner, sitting around in the back booth all the time, mostly during winter time when it was too cold to sit on the corner, anyway the guy that worked behind the food counter was gay, every so often each of my buddies and I received a blow job from him. None of us were bi we just wanted to get our rocks off. I never once thought of doing anything with another guy, wasn’t my thing, after all I was straight. One Saturday night I was horny and wanted to get my rocks off, didn’t have a date and the guys were nowhere to be found so I stop over his apartment which was only a little more than a block from where we hung out and the restaurant. Already had a few drinks, just a light buzz. Rung his bell and he buzzed me in, I remember he was watching “Sonny and Cher” at the time (showing my age here) I had a few more drinks while watch TV, I was feeling no pain by this time, not drunk but getting close, anyway got bored and was horny so I walked into his bedroom which was right there next to where we were watching TV…striped down and laid on bed waiting for him to come in and empty my balls. While waiting pretty much passed out, next thing I know I was woken up maybe 15 minutes later on my stomach and feeling him on top of me rubbing his lubed up cock up and down the crack of my ass, I figured he wanted to get his rocks off by just rubbing it between my ass cheeks and Cuming on my back or ass, being a little drunk I figured it couldn’t hurt just to let him do what he is doing, so I let him continue, all the time acting like I was pretty out of it and not realizing what he was doing to me . I could feel how hard he was and he seemed large, I always just got blow jobs from him and I was the only one naked when I got blown, so I never seen his cock before so I didn’t know how big he was, anyway he continued to slide it up and down and it did actually feel ok, a couple minutes later to my surprise I felt him start to enter me, before I realized what was going on he was inside me, I was surprised it wasn’t hurting but actually it felt ok, about a minute later he began to cum, I could feel him throbbing inside me for a good minute, he pulled out and he went into bathroom, not knowing how I should feel about what happen I was confused so I just laid there. He came back in and begun to blow me, I did cum rather quickly after he started, after getting every last drop he got up and went back to the living room, I got up a few minutes later and began to get dressed but felt the need to go to the bathroom, he must have had shot one huge load in me because an awful lot came out. Believe it or not that was the last time I was with another man but always thought of that night and what had happen to me, 20 to 25 years later I began to think about it more and more into my 40’s when my wife and I began swinging with other bi couples, only then have I been with another guy, bout 4 times as a couple. And that is how I believe I got curious about being with another guy.