Not a bad idea. When a relationship goes wrong and you can no longer live together anymore, it's easier to go each their own way, while when you're married there are big divorce costs and a lot of other **** that comes along with it, especially when there are children involved too.
There are also men out there who see women as a break. No-one can know for sure if a relationship will work or not, so it's all about taking chances. There's no 'ideal' partner, but when you feel in your heart 'this might work' and you made sure you have talked with each other a LOT about every possible subject to get to know each other BEFORE the relationship begins, then I think it will work. It's about give and take, and find compromises that both partners are happy with. If you doubt too much about to have children or not, then it's better to chose to not have any children. Once they are there, they bring a lot of responsibility for a whole lifetime ;-) !