I never thought of being with a man until I was 45. It was the internet that sparked my curiosity. I first discovered shemales on the internet and was very aroused by men sucking shemale cock. I realized that cock was really hot and I wondered if it might be fun to suck one.
That lead to a nervous craigslist encounter with a very nice guy who lead me patiently to suck my first gay cock. From there, I would be a "mostly str8" guy but once or twice a year, I would find a guy and suck his cock (and get sucked myself). I never thought about getting fucked. No guy ever suggested it and I never wanted to top. I never felt like a top. I knew I was a somewhat feminine cock sucker though and I had experimented with penetrating myself with dildos which was exhilarating.
My first bottom experience would be a complete surprise. I met a much older man who was 70 years old but in surprisingly good shape. He had a very nice rural cabin where we met. I was nervous as usually but he was very patient and kind. I took time to get to know him. As we talked, I came to learn that this man was a real intellectual and accomplished retired history professor which several books to his credit.
We become more relaxed with each other and at one point, while we were both still fully clothed, I hugged him from behind while he was showing me one of his books. He invited me to go to the living room and asked me the get undressed and lay on the couch. I laid on the couch while he stood about five feet away and undressed.