I could understand if your regret were not dating, but is your only regret a lack of sex? The "nice women" would be averse to marrying you if your number got too high. From the perspective of a marriage-worthy woman, it's fine to be a virgin till 23-25, and the ideal number for a 30-year-old male is probably 1-6.
How old are you? It seems that the odds get better for a guy until age 35. When you're 20, the age range of women you'll be able to date is very limited: approximately 18-21. When you're 35, it's 23-40. Gender ratios also improve (from a male perspective) dramatically as you age, with noticeable effects in dating. I'm 25 and loving it; I definitely don't miss being an acne-pwned, insecure 19-year-old.
Also, if you're looking for marriage-worthy women, have you considered moving abroad? The only reason I still live in the US is that New York is very, very international. I would not be able to stand it if the only women available for dating were white, suburban Americans.