This is called living in limbo, and it's very common. I inhabited this state for nearly 2 years. It's not easy! I felt like I was at war with myself every single day. The fear of breaking my child's heart was very real for me, and in a way, I'm glad I put off the divorce as long as I had because she was a couple years older (nearly 16) and handled it quite well.
It's not easy letting go after being attached to a person for so many years, even if they're no longer the person you married. My ex and I were aligned in so many ways, and he used to despise cheaters, but then he talked himself into believing that his situation was different because it was "just for sex." People who cheat aren't usually evil, terrible people, but they can be very bad marriage partners.
There's a saying that when the pain of staying is greater than that of leaving, that's when you'll go. Same with, "when you know, you know." I found both statements to be true for me, but it was hellish living through it. It's still painful on some days to think of everything we could've had (32 years together at the time of divorce).
Check out the "Fear vs. Reality" thread at the top of the Divorce/Separation forum in case fear is the main thing keeping you stuck.
How are you feeling about your WS - are they remorseful? Are they making amends? What make you think the "right" thing to do is walk away?
[This message edited by NoThanksForTheMemories at 11:01 PM, Wednesday, October 21st]