How to leave

I'm in a relationship with a guy I've been with since I was 15, we've been together for 6 years now. Long story short, he's not physically abusive at all but he is controlling and has an explosive temperament; extremely easy to anger. I know I dont want to be with him anymore. I want to leave, but I dont know how. I've tried leaving twice before. First time he accused me of cheating because he confided in his brother that I bad been emotionally distant, and his brother told him I'm probably cheating. Second time, I dont really remember, but it was over some dumb argument he started as well. I went back both times because I felt bad. I want to leave, but I'm not sure if I should confront him in person again. I feel like if I do that, he'll guilt trip me to stay again. I almost want to leave while he's at work and leave him a note, but I don't know if that will make things worse.

If you've ever had to leave a toxic relationship (especially with kids involved), how did you go about it?

Or, what advice can you give me to leave and be gone for good?

We have a 3 year old son together, also. Another reason why its been so hard for me to leave; I feel like a POS ripping this "family" apart. But I just cant take it anymore. I've been so unhappy for so many years.