Step 1: Please
Look, if your guy suffers from PE, you don't have to get into a whole angst-ridden conversation about it that's going to make both of you feel like getting on a "fast track" away from each other. In fact, you can work on his problem without him ever knowing you know it's a problem. And you can make it a whole lot of fun.

Tell your guy you want him to experience the ecstatic pleasures of male multiple orgasms: You're going to bring him as close to the edge as possible, but he needs to help you by letting you know when he's about to go over. By bringing him close to the point of ejaculatory inevitability, but not past it, he will experience one or two pleasurable orgasmic contractions, which will expel some of the sexual tension that has built up in his pelvic region. Make a game out of bringing him in and out of his "peak zone" and you're killing two birds with one stone: giving him the pleasure of male multiple orgasms and helping him last longer. And if he does come too quickly (which is bound to happen as you both get the hang of this), don't make a big deal out of it—it's all part of the fun.