Tell him to slow down, spend more time in foreplay to get him further ahead than where he is when you usually start. It could also be he thinks he needs to wait for you to orgasm before he does. If you're getting off that much sooner you're losing feeling, then getting him closer before you engage in intercourse shouldn't affect it, and even if he gets off before you, he should remain hard long enough for you to finish if you're finishing relatively quickly.