This is similar to other answers I've given here, but I'm going to assume that when you're by yourself, you get erections & ejaculate normally, right? So that ells you there is no physical problem - this is a problem caused by worrying too much about your own performance. When you meet a new girl, don't jump straight into intercourse with her, even if you're sure that's what she wants. Tell her you really like her, you want to spend the night together, but that you want to take it just a little slow. First time together, just explore each other & please each other with hands, mouth, whatever, I'm sure with the pressure to 'perform' off, you'll be just fine. Then after a couple times together you'll both be feeling very comfortable with each other & then you can move on to intercourse when it feels right. I'm betting your confidence will be good at that point & you'll both be really wanting to do it & you'll have a very enjoyable experience. Also, remember most women don't orgasm from intercourse anyway - they need manual or oral stimulation to get there, so I'm pretty sure if you give her a few really good orgasms before moving on to intercourse, she's not gonna mind one bit!