You're doing great as well! I'm glad you got a "new" pair of pants. It is encouraging, isn't it?
I'm in the military, stationed in Japan with my family back in the DC area. I'll be solo until next April. I absolutely hate being away from them, which is causing a lot of my problem keeping on track. On the other hand, that's what gives me the spare time to be able to post here and do so much exercising at the gym.
I have a great kid-participation exercise you might want to try before they get too big. I call them Jimmy-ups, although unless your son is named Jimmy that probably wouldn't makes sense for you.
Anyway, lie on your back with your legs curled up so your quads are touching your chest. Small son gets on your legs below the knees and wraps his arms and legs under your calves, like he's lying down on a really skinny horse. You hold his shoulders (to keep him from falling onto your head when you start) and do leg-lifts- lifting your feet up without moving your upper legs.
It's fun for everybody. The only problems is they want you to do WAY TOO MANY. Now that my son is almost 60 pounds, the most I can do is about 20.
Keep going! I, too am looking forward to posting our success stories.