Babies and marriage

Why is it such a stigma in our modern world that you should be married before having babies my hubby was married twice before he met me and doesn't really fantasy having a third wedding even though I've never been married it's not a big deal to me we have an 8 month old and are quite happy with out a wedding eventually I think we'll get married just to be safe legally on case something happens to one of us but probably not for a long time 3-4 years from now we've already been together 4 years and I don't really think it's a problem