I want to share this professor's Youtube video with you. She talks about not making excuses for your partner's bad behavior. She uses the lens of narcissism, but her advice can be applied easily to your situation.

Do not make excuses or justifications for your boyfriend's behavior. You can't change him. Only he can change himself. And he has to become sober on his terms, not yours.

You can't set a timeline or make demands on your boyfriend's alcoholism recovery either, because you are not the one with the addiction -- your boyfriend is. You say you want to follow the plans you two made with each other, to grow old together. Well, those plans probably need to change if you want to be with a man who has a fragile core sense of self that has caused his alcoholism.

You will have to attend AA meetings for spouses/partners of alcoholics to get your own support and also be comfortable with your boyfriend having a female sponsor if he doesn't get a male sponsor.

You will also have to remove all the triggers for his alcoholic behavior if you two live together. That means, no going out to eat, no going to bars, not drinking around him, not having alcohol in you shared living environment.

Are you ready to take all of those responsibilities on? For the rest of your life if you truly want to be with your boyfriend for the rest of your lives together?

Explanations -- like you are giving us -- are not excuses. Knowing "why" something is happening is comforting to us. But, what we do with do with the information that explains the "why?" Explaining your boyfriend's behavior doesn't excuse it, and it shouldn't excuse it.