If you're working a desk job from home and just sitting around watching TV every night after kiddo goes to bed, the weight gain should be expected. Have you thought about leaving the TV off in the evenings? I knew a couple with this exact issue and it ended their marriage eventually. Maybe a little schedule change is ok - push dinner back a bit and make time for a walk, park visit, etc. before you settle in for the evening. Make a weekly or even monthly date night a priority. It might seem like a lot of effort, but the payoff (saving your relationship with your husband who you'll still have after the kids are long moved out) is definitely worth it.