Well, this person isn't exactly old, but that's the price of loving someone, the pain of losing them and even though I am going to lose them, I wouldn't have missed out on loving them for the world. I hear what you are saying about the Beast, it really doesn't have any reasoning facilities at all. Just the sheer pursuit of pleasure.
I had a hard time coming to terms with this hard fact when I first started reading Trimpeys book. I didn't drink for pleasure, I drank because I was stressed, because I was depressed, because I wanted to be numb, blah, blah blah said the Beast. But, I realised it was true, I drank for that first buzz. Alcohol doesn't numb me, it gives me a buzz. It doesn't take away stress, it just gives me a buzz to enjoy instead and it doesn't help with depression, just helps with getting a buzz on.
If it really did not give me that initial buzz to enjoy, I wouldn't have done it. It caused me so much trouble, but for the buzz, I would have found another way to relieve stress, I would have got anti-depressants for depression and the only time I have ever felt numb is novocane at the dentist, and I wouldn't want that feeling all over my body and mind! But of course, those were just excuses the AV came up with for why I should drink.
I agree, your Beast would think the thought of pain is nothing (as it doesn't remember any pain) compared with the buzz It would get from the opitates (which it does remember) so would happily wish pain upon you to get It's fix
As for where I am now, why would I want to feel chemically induced pleasure at the saddest point of my life so far? It would be a massive insult to my loved one, as you say.