Whether circumcision affects a man’s sex life depends on which study you believe. A Canadian study found no difference in penile sensation between circumcised and uncircumcised men. However, an American study found the penises of circumcised men less sensitive than those of uncircumcised men.–Health Club
If the American study’s results can be trusted, I’m not sure that reduced sensitivity is necessarily a disadvantage given the prevalence of premature ejaculation among men. Men actually BUY desensitizing creams to control the problem after all. It’s just common sense that an exposed head would become less sensitive than the covered head of an uncircumcised penis. The question is whether that lessened sensitivity is enough to reduce a man’s enjoyment of sex.