Colin, I know this has been a long and difficult journey to reach this decision. Good for you, now be peaceful in your mind. Now's the time to step up the exercise, increase your walking and try to get as fit as possible in the time remaining. AS an
open guy, I can tell you that walking will be your best ally both before and after surgery and you can take advantage of it now.
There's several lists here for things to have, prepare and do both before and after, so dig around in the search, or ask and I'll see if I can post some of them for you. Spend plenty of time with your partner, if you have one, gets lots of lovemaking done between now and then...