Emily, my dear,
Ending a relationship, even a bad one, is *never* easy. It sounds like you're waiting for the 'final straw' that will cut your heart off from him totally and you'll never look back. Stop waiting for that, that's not how it works.
A year ago, you'd have probably said that any number of the things that have already happened would be a 'final straw' for you, but they haven't been, have they? If it was a girlfriend of yours, instead of you, you'd have probably advised her that any one of the things you've told us was 'final straw' material.
No matter how much you bail him out, he'll always get into deeper and deeper problems. Thank the universe you haven't given him your savings!!!
There is no last straw. No matter how bad the abuse (emotional, mental, physical, financial) there are always women ready to take men back...sometimes from Intensive Care units where the men put them!! The heart always softens. There's always that time, when the memory of the pain fades and you're thinking of the good times (and trust me, the rarer they are the more women treasure them as proof), that you cave and take him back. In addiction, there's always the urge for 'one more time...one last time.'
The only way to get out is to say, "It Stops Here. It Stops Now. No matter how I FEEL, this relationship ends NOW." And ACT on this! Make the decision and stick to it no matter how hard it is, no matter how much you love him at the moment, no matter how you feel.
Don't hem and haw, don't try to end it a little at a time. Do Not, for God's Sake, wait for the 'right time.' There is no right time. Only now. Every minute past now is a minute wasted in an abusive relationship.
Just End It. Tell *him* it's over and that's final. Tell your family, tell your friends, that it's OVER and you need them to help you not cave in. Leave town or at least leave your house for as many days as you can.
Mourn the loss of your hopes and dreams for the relationship. Call your girlfriends up, get a couple of bottles of wine or whatever, and go through your pictures and mementos and have a good cry...then burn or put in storage anything that might cause you to relent and take him back...this is a funeral for the relatioship, remember. It's over and there's no going bck.
Then get on with your life and keep away from him , and keep him away from you...at all costs.