Going from sharing a one-bedroom place to living in a loft to two people living in a house to me having my own place by myself has kind of mirrored my career... small steps to bigger, to bigger, to now having a steady job.
It couldn't be a simpler answer. Marriage doesn't really mean anything to me. I feel like in many ways marriage is more for the families of the couple than for the people involved, so I don't gravitate to it.