it ain't rocket science, horriblethisis - you don't NEED a reason to end a relationship.....you don't have to STAY with someone just because they are NICE to you. said gently, rarely does it HURT them as much as we think it will...because we filter it all thru our ego.
he drank from the day you met...THAT is when you should have held to your own boundaries about not wanting to be in a relationship where the consuming of alcohol in mass quantities was involved. he showed you who he was right out the gate....like a race horse. you can't then expect him to change into hummingbird.
this has been nice, but i will no longer be seeing/dating you. i wish you the best.