How do I leave her alone?

So I was with my wife since 2005. She changed me completely as a person. I raised her 3 kids and had one with her myself. Recently became a grandparent with her. We split almost 2 years ago and recently got back together for about 3 months before she decided to leave me again. We are still best friends and parents, my daughter is about to turn 17 and my 25 year old stepson lives with me. I'm not over it but I recognize that I need to reduce my interactions with her to heal myself. But we talk every single day. I know I should just cut her off but with my daughter's birthday and our grandkid there's just a lot of talking back and forth. I really don't know what to do