Pursuing a woman who has a boy friend as friends at first

How to pursue a woman who has a boyfriend. This woman I'm interested in is dating an on again off again boyfriend. I am interested in her but I want to be friends for now. Basically I'd like to get to know her better and make sure its worth mak8ng both of our lives more complicated. I think I screwed up a bit when after we went out for coffee I hugged her twice before leaving the car- she had been a bit touchy in the coffeeshop but nothing that clearly crossed the friend line Should I apologize and explain I really want to just be friends to get to know her better for now....