We have been together 5 years this month and are still not married.
It isn't that marriage isn't important to us - his parents have been married 30 years, mines 29 years and they are all still happy.
I'm the first person in my family to have a baby when unmarried, OH is only the second (his cousin has two kids but their wedding is booked for next year) - marriage and family is really strong in both of our families.
We are just as committed to each other now as we would be if we were married - it would be no easier to separate if we were married since we own a house and our baby is due tomorrow!
The only reason we haven't got married/engaged is because we have always ha other priorities - at first we were quite young (21) and wanted to go on holiday, so we did some really nice holidays. We then started renting a flat together. My OH got a new car. We saved for a mortgage. We renovated our house. Now we have a baby.
I know he is just waiting on the "right" time. Financially we are comfortable but there have always been things that we feel give us more security than a bit of paper.
If being married is reallmportant to you, you need to communicate this to your OH and maybe set a timescale of things you need to achieve first, like maybe paying off debt or whatever. Or if it isn't financial, is there something else he is waiting on? For my OH, he didn't want to be the first one out of his friends (silly reason I know!) - his friend got engaged in the summer and he is much more open to it now!