As for marriage/cohabitation, I never lived with my ex before marriage, both of my sisters lived with their spouses. And despite what research says, I am the only one whose marriage has ended....
Wow, I never thought about it, but I have the exact same experience. Two sisters, they both cohbitated, I did not, they are both still married. Hmmmmmmmm
"You can't stop the waves, but you can learn to surf." Jon Kabat-Zinn
