The wife and I were discussing this. I contend if a guy is curious enough to try, he's, in my option, more likely to do it more. The wife thinks many men are curious enough to try, but it's a one and done. Curiosity satisfied.
I know guys who tried it once and they've never done it again (that I know of). Some decided immediately after the fact that they didn't like it, it wasn't what they expected or thought it would be, or their guilt rose up to make sure they wouldn't be doing it again. I've probably had more than three or four guys who gave amazing head their first time out and... curiosity satisfied, thanks for the experience, back to chasing girls. And that was with them being with me. I've talked to many a guy who confessed that, uh, yeah, they tried it once and hasn't done it again - one such guy said that he tries not to think about it because if he does, he's gonna want to do it again and he might really like it too much (and people would think he was gay).
I think you'd make yourself crazy trying to quantify this; it's why when I'm talking about such stuff I use "a lot of guys" or something else "generic" because I don't dare try to offer up percentages and the only time I actually quantify things is with my own, personal experiences, i.e., 80 to 90 percent of the time, I swallow. How many guys are curious? We may never really know because like Jumper 58 said, how many guys would want to admit to being curious about sex with men? How many have tried it? A lot. Pick a number and you might not even be in the same neighborhood. How many curious guys actually took the plunge to end that curiosity? I dunno except for my own experiences; if I was with 10 curious guys, I'd say that 7 would take the plunge, 2 would defer it to some other time, and 1 would be headed for the hills as fast as their metaphorical legs could carry them. For those who are curious and haven't dived in yet, believe me when I say that "for some guys," being in the moment of truth when they really have to take a guy's cock in hand and put their mouth on it is scarier than just thinking about it. How many guys chicken out in this moment and generally speaking? A lot. I can say that in my experiences, 1 out of every 10 guys has chickened out with very cold feet when presented with my dick or I'm about to go to work on his prick and... he says that he can't go through with it. And keep in mind that I've given 100 or more men their first experience. I tried to put a number to all of my activities with men and... gave myself a headache and realized that it's not a number's game or, as the kids say, it's not about a body count, is it and when you consider that I've been having sex as a bisexual for 60 years... try to do the math because I sure can't.