I dont know if this will work for you but I think it might be working for me. I'm also 3 years out and have had trouble with plateaus and set points in my weight too. I read recently that your body will adjust to whatever you do, so you can jump start things by NOT being consistant. Change it up as much as you can. Don't do the same 'diet' every day. Don't follow the same eating or workout schedule. So, since I usually dont eat breakfast, I have been eating breakfast sometimes, eating different things than usual for lunch or dinner, doing a different kind of exercise at a different time than normal. Try learning a new sport (racquetball is fun!), or learning to cook a new cuisine.
I just started this a week ago but I lost 3 pounds! I am at my lowest weight this year now.
A few other things I do that may or may not make a difference- I always jog to the car (like I'm in a hurry!) when I go somewhere, always park far out in the lot so I have to walk farther, always take the stairs, always do a few extra squats when I have to take clothes out of the dryer. I work at a desk so I time my tasks so I have to get up and move around as frequently as possible. Just to file something, check the fax machine, make some copies, etc.
You can do this! It is within your control!