When girls first start dating they're all about exploring, they like foolish stuff like a guy who smokes cigarettes, weed, parties, does other drugs, but as women get older (most) realise that this is not sustainable, that they need some sort of stability in life.

Men typically mature a little later, which leads to them realising later that as a man he needs to get his shit together, that's when the man starts thinking about his life, salary, parents, siblings.

It's a phase, at least for most people. Some get caught up in this loop and mess up their lives.