I don't believe in marriage. Marriage is a business partnership jointly endorsed by the state and the church, two illegitimate organizations. You have relationships and make commitments, if you have children together, hopefully you raise them as a family unit. But nothing is permanent. If you do a good job raising your children, they will leave, because they will have outgrown the need to live with you. If you are a functioning human being, you will always be growing and changing as well. Sometimes people grow in different directions. It's not normal to expect people or relationships to remain static for 50 years. If your life has meaning, and is about something bigger than yourself, you will not fall to pieces by a change in relationship status. I think our society is very dysfunctional, and most people exist in delusion, not even knowing themselves.