I don't have a clear answer either. The longer someone is in a relationship, there is more that is invested in that relationship. It's been a couple of years since we have not been intimate...for various reasons, but my wife seems to imply that it has been longer. I'm trying to work with her, we've seen a counsellor, but she doesn't want to go any more since she thinks she's been clear as to what has to be done...by me.
The thing is I've been questioning myself as to whether my needs are being met, and my assessment is that they are not. You see in addition to all this, I'm also bisexual and it's been 20+ years since I've been with a man. There are things that my wife can't give to me, because she physically doesn't have the right stuff. But I chose 17+ years ago to be with her and accept a heterosexual marriage.
Now though, we are not intimate at all. So I don't get straight sex, don't get gay sex or even basic intimacy (kissing, hugging, cuddling). So what is left? Family, finances and friendship...
I don't know if that is enough? I feel guilty when I think seriously about leaving my wife for a man. Am I willing to give up the friendship? Lose money in a divorce? I don't know...though there is a part of me that is curious to find out if I could have a better relationship with a man because it is easier to know how a man thinks when you are one.