Split with a 2-3 year old. What is it like?

Hi guys.  So glad this board is here because I really need to hear some first-hand experiences.

I've been married to DH for almost 10 years, together for 18.  Things have wavered between excellent and horrible since DS was born 2.5 years ago.  DH is a problem drinker (like pass out drunk 5 nights a week).  I've lost so much respect for him over the drinking and was already contemplating issuing some sort of ultimatum about it.  Then last night (while drunk, of course), he got so angry he threw entire drawers(one with knives!) across the room and then slammed me into a wall.  All while our two-year-old was watching.  

I don't love him in any passionate way, and I don't want to be with him.  But I also don't want to miss a minute with my son or deprive him of the experience of a mostly happy two-parent family.  If you left when your kid was very young, how was the experience on them, and you?  I see that so many of you are struggling, and worry that leaving now might be overreacting.