Quoting BG Secrets:" I stay because I still love him so much. The latest thing is he keeps searching and searching for his ... [snip!] ... happen again just so I can say "Alright this time was enough I'm leaving" but I never have the strength to. I feel so stupid."
You're not stupid. He's probably taking advantage of the fact he knows you are weak and won't go. You need to muster that strength though because you don't want to set the example for your son/daughter that it's okay to treat people/be treated that way.