And, if it helps at all, your kind of path of initiation into sex from hookers to (in those days) marriage used to be very, very, very commonplace. It is certainly not commonplace now, but still nothing to cause you to feel SO concerned about your future with women. You will be OK. Women are women. It is not that you have been having sex with extraterrestrial aliens for 6 years, have gotten used to them and now want to make a grand leap of faith and switch to the women of the Earth.

You have identified the main issue correctly. The main issue with relationships not mediated by monetary exchanges is the possibility to be rejected. A hooker is bought so she cannot reject you, and you find solace in that arrangement. Now you are about to graduate into the world where you can be rejected.