I think these days it would be wise to co-habitate but not marry. One can still have kids and live together without marriage.
Infact a friend of mine is doing just that, he has been with his partner for 8 years, has 2 children and they are not married.
They both maintain their finances separately and pitch in jointly for shared expenses… I guess it works out great for both of them as they seem very happy.
I think when people get married then expectations get very high and one side is always disappointed that they are not getting enough.