I was a volunteer at the safe house when Colorado Springs opened its very first shelter (that was almost 40 years ago!). The Springs has GREAT resources for DV. Please know that you can also report the sexual violence you experienced.
I've worked in the DV field for many years (retired DV prosecutor), and you are in a very dangerous situation. I know you feel embarrassed and ashamed--most people do, when they first disclose what's happening in their relationship. But it is in no way your fault.
If you close on that house with him, you are adding one more financial complication that ties you to him. You don't have to get a divorce unless/until you're ready, but don't make your situation worse than it already is by making it more difficult for you to leave him if you have to (and that time might be sooner than you think). And please don't even CONSIDER starting a family unless he becomes sober and addresses his abusive behavior. The alcoholism and abuse are separate issues. He may only "act out" when he's drinking, but most alcoholics are NOT physically abusive. The fact that he behaves this way when he's drinking means that on some level he feels "entitled" to act that way toward you. And simply getting sober will not change that. The only abusers who tend to change are those who are HIGHLY MOTIVATED to change, and who undergo treatment to address those underlying issues.
Please take action to protect your safety. And as far as being "alone for the rest of your life," that is unlikely to be the case, but even if it were, it would be better than living in terror of the next incident where he gets drunk and beats you up, rapes you, or worse.