Mate I'm with you there to some extent; my wife is a SAHM with a 5-year-old, an 18-month-old, and one on the way.

CP had some good suggestions. What is the background behind the antidepressants? Was she diagnosed with post partum depression (PPD)? This can play havoc on a woman's mind, especially if she was susceptible to depression before. My wife had PPD with both's a hard thing to go through.

Join a gym that has a nursery. This will kill several birds with one stone: it will let her work off the baby weight, making her feel better about herself. Working out will improve her mental attitude and give her more energy. It'll give her a break from the kids for an hour or two at a time of her own choosing. The kids will be socialized. It'll give her something to schedule her day around. We do this and it's a godsend.

I know what I've done in the past to contribute to it

In addition, I've tried my best to stop being critical of her, which I've done in the past and has led to problems.

Stop doing it altogether. Get the book 'Love Busters'. Read it and learn it. Look, the SAHM is in charge of the house and has her hands full already. If you think you have a better way to do it, either do it yourself or keep it to yourself. Suggesting/micromanaging the SAHM is not kosher.

Consider a church-run mothers day out program, or a Montessori school, or a gym class/academic program. Even a couple days a week will help.

Me - 44
DW - 39
Married 16 years