My view is that each person should do what they think is right for themselves, their relationship, and their happiness. Whether that be waiting to have sex after marriage, or having sex with one person and then marrying them, or having sex with whomever you want and not marrying any of them. All of those things are okay, you, as an individual, just have to decide which one is right for you.
What is right for me is to be mentally, emotionally, and physically close with my boyfriend of two years. We are in love, and the intimacy that sex gives us is something that only keeps us closer.
Don't let anyone talk down to you for your decisions on what to do with your own body. Don't feel inferior because you had sex and others disagree with it. Don't feel inferior because you haven't had sex and others think you should. Make the choices that are right for you.