It was all going so well, until you reached the crucial point, then, bam (or rather flop), you hit an obstacle. Remember that it doesn’t mean that he doesn’t want you, it can mean quite the opposite in fact. Face to face with a woman he really likes, he can’t take the pressure and loses his erection.
He could be coming out of a long-term relationship, in which case it may be hard for him to find himself in bed with someone else, after years of sex with the same person. Don’t dramatise the situation, tell him that you’ve got all the time in the world, that you’re a little nervous too and use your hands to try to get things going again. There’s no law that says sparks must fly the first night, a fabulous relationship could start with an evening of kisses, cuddles and massage. Give him time.