I'm not an expert on these things by any means, I am a dreadful boredom/comfort eater myself (brought up that way by parents who had major issues around food), but I would say you've identified various things going on in your life that sound really difficult and it sounds as though the over-eating is the symptom and not the cause? So although there's some 'standard' advice that could be given about healthy snacking, just not having the snacks in the house, making and sticking to a diet plans etc., it would really only be a sticking plaster rather than a true solution?
Some of the things you mention are definitely not things that can be 'fixed' overnight (I've been there too!) but perhaps you can pick one area to address at a time. So could be trying to up your exercise, or doing some mindfulness or meditation for your mental health, or perhaps having a heart to heart or even relationship counselling with your DH?
In terms purely of the eating, I do have a relatively rigid 'diet plan' (not trying to lose weight ATM but maintain a healthy weight) I stick to that I know is healthy, has enough of the nutrients I need etc and does also allow for some treats so I am not totally deprived. I know it's probably not the most emotionally healthy thing in itself to have to stick to a daily 'plan' rather than being spontaneous, but it does help me separate out what is my body saying it needs food for fuel, i.e. genuine hunger, and what is my mind saying it wants food as occupation/comfort/distraction/whatever. It really helps me to think things through when my mind is saying 'I want some crisps", I can 'reply' (I sound a bit mad having this dialogue with myself 
): "you've had a healthy dinner so this is just you wanting a treat. crisps are on the plan for Saturday night with a film and some wine, do you really want the crisps now and then you can't have them on Saturday, or can you wait?", nearly always I find I can wait whereas if it's just a 'no I can't ever eat crisps, crisps are bad' mentality I just think "fuck it, I want some", and have them anyway...
I have some techniques I use when I do get the desire to snack (like you it's nearly always in the evenings) - a combination of things that satisfy the sensory part of eating like having a nice (0 or low calorie) drink or chewing some gum (I know some people find gum disgusting but it helps me and I only chew in the privacy of my own home!), things that are emotionally comforting like a hot bath or doing some nice self-care like doing my nails, and things that occupy my brain like watching favourite telly programme or doing something with my hands.
It's not easy and especially as you have a baby you need to go easy on yourself, but small changes should be possible and sustainable. Good luck!