That question is worthy of an essay-sized response. My short version...A good chunk of society, most religions and many cultures still place a lot of pressure on girls/women to remain virgins until marriage. Holding up female virginity as sacred is a ridiculous standard that divides women into "******" or "good girls". Some women are so brainwashed that they find it difficult to accept their sexuality. Sexual compatibility should be part of the courtship.
Religious? Lol. No.
Just self morals.
There is more to life than just sex you know