Lou please don't mistake for one second that because we are all in different places in our relationships that we don't or didn't love our significant other with all of our hearts. My husband was the most amazing man I ever met in my life until the alcoholism, and then he wasn't, he became my worst enemy. Many stay for what they thought could have been, but the fact remains, the past is the past, you may never have that again, you can only deal with the here and now, protect yourself and do what's best for you based on the current state of affairs.
I encourage you to really think about what is best for you, I pray that you don't end up like me...resentful of the time I wasted.