When I was 18, I think I thought I would get married before I had chilldren, then at 24 I had two children 14 months apart but neither of us wanted to get married so we didn't. At 34 I had another baby, and still didn't want to get married then at 40, I woke one morning and decided I wanted to get married so at 41 with three children we are getting married. Until I woke up that morning I was adamant that I didn't want to get married but then, it suddenly felt right and other half agreed. I almost think I have waited this long so the children can be a part of it.
One thing that did concern me, was that the children had a different surname to mine. It didn't bother me, but I was worried that they may have got grief at school and if they had have come home upset or had said at any time in their lives that they were having a hard time about us not being married we would have got married there and then but they never did.
I think it depends on the couple if they want to have children before or after marriage, how they feel about it. Circumstances count into this as well. My first two were not planned (who would plan to have have two children only 14 months apart ), but I wouldn't be without them at all, they are absolutely wonderful and always have been. I don't think it really matters in this day and age, but what i would say, i would prefer my children to be married and settled before they had a family but if they weren't I couldn't say much about it, and would obviously support them all the way (but i think thats more to do with them wanting to be settled) . I'm not sure if it is so much old fashioned as just how you feel.