You cant because fear is the opposite of love.
Love gives, fear holds back. Love is more concerned about the other person, fear is more concerned about yourself.
If it's mutual, take the plunge and fall together.
you have no choice on that matter..it will happen eventually..nature sets a balance..to know the bad is to know what is good for example..
not risking is the greatest risk too ,they say..
Sometimes Love just takes you by the hand I'm afraid ..and you have no choice but to fall.
Sounds like your parents taught you dogma about marriage and sex. Can't think of other reasons why the issue would arise.
then jump ;)