Good question. Mine has been on the rocks for over 30 years (we haven't been living together, but have no court order clarifying our relationship).
We underwent much marriage counseling during the early part of the marriage (at my insistence). I acknowledge the good aspects of the marriage, but the not-so-good aspects outweigh the good--the greatest problem being a marked difference in what one might call "core values."
All in all, a person has to choose to be happy, regardless of what is happening "out there." Since splitting up, I have come to have a healthy respect for myself, and, truly, you can't give love if you first don't love yourself. Don't misunderstand me--I'm not talking about the selfish love that comes with puffed-up pride, but, rather, self acceptance that is wholesome enough to be shared.
I have two thoughts from spiritual instructors regarding marriage: 1) everything is a marriage; and 2) if you have been offended, it means you still have pride--think about it.
No one person is at fault in a marriage. If the vows of matrimony aren't working, the couple shares the burden 50-50. Life is as much a perception as it is an action.
At this stage of my life, the potential for "saving" the marriage is doubtful, to say the least, but if were to happen, it would probably begin with the healing of my elder daughter's relationship to her father (he still doesn't know he has a new-born grandson because of her refusal to communicate with him).
I confess I seem to feel better about myself without the man's presence. How many years will it take to reunite or finalize a proper divorce?
Only time will tell.