As someone who had this mindset from social pressure in their younger years, you should get over yourself. A friendship and a dating/sexual relationship can be separated by being able to let go of the feeling of being rejected.

Because the friendship is going to end, one way or the other.

Your feelings of being rejected are valid, your reaction is counter productive in the long run. Try to be friends, let the rejection go. Focus on putting yourself out there to find someone else.