I've had my Ileostomy for nearly a year now, which is below my waistline, and I haven't struggled that much with pants. I tend to either wear trousers with waistlines above my bag or they just go straight across it, but not too tightly.
As for dealing with the hard parts of an ostomy I take things on a day-to-day basis. I've never been happy about my ileostomy, as when I had my surgery it was completely out of the blue (I didn't even know I had Crohn's) so I never really had the benefit of being ill (if you can call it a benefit!?!?). However, I couldn't be happier with my life, I can do whatever want whenever I want. The only thing that holds me back is my confidence due to the ostomy but over time I'm overcoming this obsticle and I'm getting my self confidence back.
Hope this helps