But trust me, if you are staying with him just because you feel like he is your only friend and it is comfortable- that may not be the right reason. You need to be with someone you can not be without, not someone you can just be with.
This is great advice! My mom told me something similar when I was with my ex in Tampa. I now realize a large part of the reason I stayed with him was because he was like my best friend in Tampa and I was scared to be alone. Although alcohol wasn't an issue in the relationship it is still obvious to me now looking back that I should have broken up with him long before I did but I was scared. And trust me, you WILL get over it and become a much stronger person.
Going to Germany sounds like fun. I've never been there but I've always been curious about going. Just focus on your trip and your school or your family or yourself in some way and work on making YOU happy with or without him. If he doesn't think you are important enough to clean up his act, find a man who deserves you!