That may be controversial, but maybe you are just doing too much. More isn't always better. Adding more exercise time adds more stress to your body. Stress can lead to weight gain.

3 hard training hours + 100 Miles on the bike per week just sounds like a lot to me. Don't get me wrong, I'm an exercise junkie too, at times. The question ist just what you want to achieve. If weight loss/fitness is your only goal, I would just try to do less.