Two kids, 8 and 6. How do I explain parents breaking up ?

I'm the father and I've been with the mother for 15 years now.I'll save you the details but the relationship has been toxic to me since the beginning and I was never able to leave her. She took advantage of me and manipulated me into staying with her.. until now.I'm done. I want to be happy. I want my kids to be happy. This thread isn't about attempting to save the relationship, it's about help and advice to best manage the kids.I love my kids and do my best to be a better father than my father was to me.My eldest daughter is old enough to understand but it still makes her sad. She doesn't want us to break up and I let her know that I understand. She realizes that her mom doesn't take care of her, doesn't play with her and doesn't teach her new things. She cried last night and it was very hard for me. I played with her and hugged her to sleep.She has been exposed to kids with separated parents before so she knows a little bit how this works.My youngest daughter is autistic. Making her understand what is happening is going to be quite challenging. She misses me terribly when I need to travel for work, in all likelihood because her mom doesn't fill in the gap.She loves her mom but she knows I am the one she learns things with, has fun with, etc.I am the best positioned to take care of the kids. I have a house and work from home, have a good salary and I've been almost single-handedly taking care of the kids, school, activities, food and everything.The mother is not only toxic but her family as well. Alcoholism is rampant, lack of education, poor, etc.I've never lived a breakup like this before and would love to have advice from other parents who may have gone through something like this before.Thanks! via /r/Parenting https://ift.tt/2yLjUar