Sex and marriage

Hi everyone, I’ve really been battling with myself on this topic. I know that sex is meant to be between a man and a woman who are married. I’ve been with my boyfriend for a while now and we both know that deep down we want to spend our lives together but we want to wait until I am finished with college before we think about getting engaged. We recently started having sex and it’s not very often. I struggle with coming to terms of the fact that we aren’t married yet and also the fear of getting pregnant out of wedlock. My boyfriend and I see a little differently on this subject. He sees sex as a way that you show someone how much you love them and desire them and that it’s super important for a relationship to work. When he says that it makes me feel as though if we don’t have sex in our relationship then our relationship won’t work. I guess my question for you all is what is your opinion on premarital sex and how that affects your relationship with god and your significant other?