My j-pouch will be a 3-parter, too. I had my first surgery 3 months ago. They won't even mention the second surgery though until I get back to a normal weight/strength (I lost 30+ lbs prior to surgery while battling a severe UC flare). I've gotten used to the bag in the meantime. Like you, I have had a few low moments that I've mourned my healthy colon from years ago. But hey, to not feel sickly anymore is worth whatever it takes!
As for where you wear your bag and what to do with the belt... I wear mine between my underwear and pants. I'm afraid of it being too constricted if I tuck it in my underwear. As for the belt - I haven't quite figured that one out myself yet, lol. I live in pj pants when I'm home and light weight cargo pants with a drawstring-type top when I'm out casually. None of my jeans fit right because they go across right below where my stoma is - and since they are low-rise, I feel like they constrict the bag too much anyways. The only pair of pants I have tried on with a belt are a pair of work slacks. But since I'm still 25 lbs below my normal weight, I can't get the belt tight enough to do anything but keep the pants from falling beyond my hips, lol.
Anyways, sorry for rambling on so much. I wish you the best as you go through the recovery process! :)
Diagnosed w/IBS: Oct. 2006 Diagnosed w/UC: Jan. 2007 (proctitis), July 2008 (pancolitis)
1st Surgery for J-Pouch: May 22, 2009 - need 2 more surgeries, dates TBD
Canasa ; Rowasa enemas; Lialda; Prednisone; Protonix; Remicade; Zyrtec-D; Toprol; various pain meds post-surgery;
Supplements: Women's One-a-day multi-vitamin; Super B-complex
Current Status: Aug, 2009 - Recovering from the 1st stage of J-Pouch surgery; temp ileostomy; 2 more surgeries to go as there was too much damage to create a J-pouch