No offense to the other guys, but forget that stuff. My story...
Was a virgin going into college. A mix of Catholic morality and growing up the "fat kid". Jerked off constantly, but so does every kid in their teens. Fooled around in college, and had sex a few times, but never really dated much in college. Just occasionally serial hookups. Lots of oral, but it seemed like actual sex was mostly saved for boyfriends or whatever. Anyway, right after college started dating this girl. First time we're at her place, fooling around, she pulls out a condom. Awesome. Really hard. Go to have sex, goes away. Oral with her, no problem. Just the sex isn't working out. I wouldn't really "feel" nervous, but obviously was, and after the first time its always on my mind.
That didn't work out and we broke up. After that, didn't want to date so much because of it. Finally went out with a girl a while later, and we sat down and talked about the whole thing (after it failed again). A little time and a few sessions, and things were ok. After that, the only problem was that she turned out to have a low sex drive.
New girls after that, it would happen the first time, but if we just had a calm talk about it, every one was ok. After the first couple girls, that was it. New girls after that were fine.
To answer "I dont buy in to the whole gay thing as I believe its a choice...", I'd first like to comment on the concept. There are many gay people who have to deal with this kind of prejudice. Were you having sex with men, then once day decided to like women? If not, what are you basing your opinion on? Nobody would choose to be gay, any more than they'd choose to be short, poor, or, you know, ignorant. Not because being gay is bad, but because of how society treats you. Right? Did you choose your performance anxiety? Yes, in the sense that its in your mind. But you didn't choose it, and you can't just decide to not have it. And that's just a psychological issue. there is plenty of evidence that sexual attraction isn't "chooseable".
Now, as somebody who's dealt with performance anxiety, its all in your mind. Porn is exciting because you mentally put yourself in the porn. So, think about it. If sex is currently a sore subject, when you see somebody having sex its not going to be fun to watch. If you have great success with blow jobs, watching one is fun. Its really that simple. If you see pictures of men with their shirts off and that turns you on, then maybe you like men. If not, you probably don't.
If you don't have wood problems in other situations, changing your diet isn't going to help much.
I'm currently in the boat you are. I dated a really crazy girl last year. She brought back the whole performance anxiety thing after a couple bad sessions. Its really tough to date when you have to worry about that. After that girl, I wound up going home with a girl I used to date. Sex, no problem. Then I started dating a girl in our circle of friends. By a decent margin, the hottest girl I've dated. First date I spent the night. Lost erection, but I just kind of explained it to her. Immediately ok, but we didn't have sex. Just fooled around. After her, dated another girl. Same problem. This one didn't get it. She thought she was ugly, then thought I might be gay. The whole bit. That made it worse. Next girl, same problem, but she was cool. After a little while, sex started working out. The last time we hung out we had sex twice that night, and twice the next morning/afternoon. However, that didn't last too long. I still honestly believe the next time I go to have sex with a new girl, the same thing will happen. Last night, in fact, I was at a party and there were two girls I probably could've hooked up with, one was very clear about the opportunity. However, forget one night stands when you have this type of thing going on. Probably a good thing, but still, it sucks.
I disagree with ForceFan on the gay issue, but my whole thing was the same. Once I'm in, I'm in. It works out. Everybody is different, but I think that's pretty common, and probably will be the same for you.
Since you're also apparently a virgin, or close enough, I'd highly suggest you attempt to find a girlfriend. Performance anxiety is tough, but the key is being relaxed with somebody. You can pretty much rule that out with a random girl at this point.
1) If you find a girl who's ok with what's happening and willing to work with you, you've got a much better shot. Word to the wise. When shopping for a girlfriend, look for one who's really nice and genuinely concerned with other people. A hot chick who's kind of a b___ is not going to help you here.
2) Fool around a lot with her. It will help you feel comfortable.
3) Occasionally try actual sex, but don't get too worried about it. Or, you know, do your best
4) Have lube around. You're worrying about your erection. If you're also worried about her being ready to go and all worked up, that's a lot of extra stuff to worry about. She shouldn't be a passive participant, but its likely that you're not going to have synchronous excitement levels. You will, after you get the hang of it. Trust me.
The viagra et al might help, but as you've never had a successful sexual relationship, I'd think you would be more likely to rely on it. Also, at 20, you could be one of those guys showing up at the hospital with the 4+ hour erection. Take small doses if you go that route.
By way of full disclosure, I'm probably going to give that a shot. From what I've read, if you get solid erections, but lose them when you go to have sex (like ForceFan and myself), these drugs can be helpful. They don't create erections, but inhibit you losing them by helping to keep the blood in there. This is exactly my problem, and could be helpful. I've been in relationships where things work fine, so the cause of my anxiety is just the first night, or nights. Since I've been with girls who freak out at a lost erection, I'm all nervous about it happening again. Just the idea that I could pop a pill and "save the day" if need be is really calming. Knowing I wouldn't have anything to worry about kind of knocks out the whole problem.
By the way, I'm generally a pretty relaxed individual, so until now the whole anxiety situation was pretty foreign to me. It sucks, but you can get past it. Until that crazy chick last year, I'd had some fantastic sexual relationships. In fact, look at it this way. When you get through it, you'll have a much better understanding of yourself. A lot of guys hit their 40's and start having problems. They can't get hard once, and suddenly they think the world is ending. You've already been through it.
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