From someone who doesn't want to marry

I hope my post isn't distasteful or wrong, otherwise I will delete it.

My gf (39F) and I (41F) have been together for 12 years. We live together, we have a cat. We haven't been able to get married for most of our relationship because it wasn't legal where we live. We could get married now, but neither one of us really wants to.

However, if marriage was something that was important to my gf, I would have married her years ago.

I can get over my disinterest in marriage, I cannot and don't want to hurt her intentionally. We are one team, if either one of us desires marriage we will do that. That is so much more important than anything else.

Not sure what the point of my post is but how can someone live with someone, have children, pets, buy a house or entangle finances and then not want to get married when the other one wants? I just don't understand it.