Should I walk away or try and make it work?

Walk away. First off you have been in this relationship for "several years". It shouldn't take that long to know if this is the person you want to spend the rest of your life with. You're both unhappy. Maybe because you both know you should break up, but it's not easy. It's the common battle between the heart and the brain. But you already want to leave. You said "...I need to just walk out" and "common sense tells me to just walk away forever". Yes, you still love her. Yes it's gonna hurt. But it will hurt more to allow this to continue. Most especially the decision to even allow you to get to know the children when there was no future determined at that time yet. That was selfish. Now they have to endure the breakup. Don't do that again, until you KNOW you're going to work out. I think you both have some maturing to do. It may be best not to date anyone for at least a year. In the meantime, get counseling and learn about your personality type, the behaviors learned while growing up, and other stuff. Make sure you are nice, amicable, gentle and understanding when letting her go. She's a single parent, and that's not easy. But you're under no obligation without a marriage license. So, be reasonable. Make a decision, well you actually have already, but stick with it. DO NOT GET INTO A REBOUND RELATIONSHIP! Those are only to help not feel the pain of a breakup and seldom work out. Please use your brain! Take care.