Pre-Seed gel

OK ladies I need some help. my husband and I are TTC for 10 months now. Someone told us to try the pre-seed fertility gel so we've tried it for about three months or so. the problem is when we use it it greatly affects my husband and he can't finish. We tried putting in and waiting thirty minutes, tried only using half the dose and both end in the same result it like makes him go numb. My question in how long is best to wait to have sex? We normally have to wait at least an hour but is it still effective then? HELP!