You have 3 major problems:
- (1) you aren't getting any break from childcare and this is leading to burnout and excerbating your MH issues
- (2) you and your husband don't communicate in a constructive way and say things you may not mean just to hurt each other
- (3) all your interactions with DH seem to be about childcare and you're not spending quality time together as a family or a couple, so you're growing further apart
The way you describe things gives me the impression you feel helpless to change the dynamic - you don't know how he can cope if you leave the house for an evening much less a job, the war in Ukraine which you have no ability to change means you're stuck with depression, etc. But you have more power than you think.
To address (1), you need to get your husband used to doing bedtime for both children. I'm not sure if you currently switch which DC you each do or if he always does DC1 while you do DC2 and so he's unfamiliar with their bedtime routine? I don't know what exactly caused the catastrophe on your night out but supposing your 2 year old wasn't doing well at bedtime and was screaming, this would prevent the 6 year old from getting to sleep - it could just be that one child's bedtime is the issue here. He probably tried to get MIL to do the other child (taking over your role) and it didn't work out. This is very fixable.
Which brings us to the MIL. You say they don't see her very often, but why's that? Unless she's horrible, that's a great resource you have for free childcare. Maybe she can come around more and learn your bedtime routine so she can follow it and then the DC can grow more familiar with her and won't be distressed by her presence?
To address (2), your DH is being cold and distant because he's avoidant. Neither of you are in a good mood right now from this. You're both having days ruined from it. Neither of you are feeling like a winner here. You have valid reasons for feeling upset and so does he. You've both made the situation worse by saying hurtful things to each other so now you need to hear that the other person didn't mean it to undo the damage.
If your DH is loving and a good person, he will respond positively in kind to goodwill gesture and won't just use it to gloat that he won. Here's how I'd generally approach it... (after the kids are put to bed, and allowing him a say in between some points):
- I hate how things are between us right now. I don't want it to be like this. You were right, I was being jealous and bitter about your trip. I feel like I don't get the fun out of anything to be honest, though I shouldn't have spoiled your excitement because of that
- I don't want your trip to be overshadowed by us fighting so I want find solutions with you together
- I feel like I can't leave the house; I worry about how you are going to cope and it makes me feel like I can't have a night out or go back to work
- One of my biggest anxieties is that you don't want the life we have and want your old one back. I know you've reassured me before that you love what we have but when we fight and you say you're stuck with us, it really hurts. I think this is also why I got jealous of your trip with your single friends.
- lately I've been getting so overwhelmed by the day-to-day routine. I really want us to have quality time together. But it feels like you don't want the same when I'm told you'd rather be out with your friends than go anywhere with me. It hurts so much to hear that because I want to do things with you
I think if you're open and honest and KEEP CALM you will get earnestness in response. You can then talk about trying some nights where he puts the other DC to bed if he hasn't been, some nights he tries to put both to bed, planned nights where you can go out without being bombarded with texts (it won't kill them to get to bed a bit later if it's not a school night and he should be able to handle them while they're sick), MIL coming over more often perhaps, whether he feels you're leaning on him too much by talking to him about your depression and what he can do instead to support you better, planning family/couple activities for the future, etc.
If at any time the discussion threatens to escalate negatively, just say "we've been talking about this for a while. Let's have a break and come back to this tomorrow ok". Then you can talk about it again when you've both cooled off and have had time to think about what the other person said.