Him liking food isn't a problem. Him steeling his kids food, including sometimes off of their plates, is a huge problem.

The dinner story: I can't believe this guy is seriously recreating that one family guy cutaway. NTA, that guy needs a serious reality check.

Dinner dad's problem isn't his appetite, it's his fundamental selfishness. There are SO MANY solutions to hunger that aren't "literally steal food from my growing children," but that's the route he decides to take every time.  Like dude just stock up on PBJ material!

The running theme of these stories is "What did you expect?" You keep eating everyone else’s food; did you expect to get more food? You keep pulling these mean-spirited pranks on your girlfriend; did you expect her to put up with it forever? You smothered your children with attention to the point it ruins every romantic relationship you ever have and now they’re pulling away from you; what did you expect?

A lot of people don’t seem to think through their actions that will most certainly cause long term consequences.

Last story, you cannot take over the lunch room.
I've been in OP's shoes and you can't win.  If you lie to the boss "to not ruin it for everyone else" then the boss is going to think you're a cheap antisocial weirdo.

2nd story: there’s a difference between “liking food” and being a complete pos. Stealing food from CHILDREN… and eating disgusting amounts of food like it’s nothing. It’s absolutely abhorrent. Idk how OP sleeps soundly staying with someone like that

That guy who eats everything in the house is going to give his daughters either the food aggression of a feral dog or an eating disorder, there's no in between.

The prank proposal: she said at the start that he liked pranks that humiliated the recipient. I think Oz was spot on when mentioning the bf was being malicious. And like, why is it okay for him to humilate people but the world will end if he's humiliated back?? Hypocrite

Dinner
This man straight up said it was worth it to eat not only his portion but also the three other people's portions in the home....

He's not even remorseful it sounds like. He's disappointed he didn't get something he wanted. Not the same as being remorseful.

You can't tell a person about a party, explicitly uninvite the person (effectively stranding them), then get butthurt that they won't lie for you to preserve your reputation. You are not obliged, but neither are they obliged.

1) The axe forgets, but the tree remembers.

2) Yeah, the husband is selfish. I have a bit of an appetite myself and it’s never made me eat someone else’s food

3) Engagement “pranks” are the worst. There’s no right way to pull one off; it just inherently sucks.

4) I do understand and in a way admire the (ex)wife prioritizing the kids, but it came at the expense of her marriage. And it turns out, the kids also ended up appreciating OP more.

5) Hijacking the break room for a baby shower you’re not invited to is exclusionary! And just what was OP supposed to tell the boss?

The dinner story: I personally have a broken metabolism. I am always hungry and have gotten used to being constantly hungry. If I don't stop myself, I can eat out my entire pantry. But that's just the thing, I stop myself. I always stop myself. I never eat first, making sure others can get some. I always hold back when there are seconds and the like. Making sure to ask if I can have what's left over when they have already clearly finished. Genuinely that dude is a monster. Snacks I can understand as you might forget about x or y or how much someone else has had so you might not realise you've been inconsiderate. But eating someone else's whole dinner?! At that point appetite suppressants might help them not feel the discomfort of hunger but it won't fix the genuine disregard of other people.

Story 3: It's a good thing he's your ex, because once he thought he had you under his control, he showed you who he REALLY is. Also, his family is garbage as well.

Wedding Post:  If Marie wanted a bridal shower without that one particular person, then maybe don't CC that one person and don't host in the office.  Like, it's not rocket science, what was she expecting to happen.

And this doesn't include Joan basically trying to rub it in OP's face.

That dad eats four people's meals and still wants more, truly some No Face behavior

My father used to eat our leftovers after us, but only on occasion after we left them for extended periods.  The difference? My father used to be homeless for a while, and it made him really sensitive about food waste. We knew, so we only held it against him when he ate something we were saving.

Since other people are chiming in with their “Story 1” stories, here’s mine.  My family had a pretty basic “the older you are, the more freedoms and resonsibilities you have” style.  Which was fine.. my older brother got to stay up later because he was older, I got to stay up later than younger brother because I was older.  And I was eagerly waiting for the day that I could finally ride my bike further than just my neighborhood, the way that my older brother could.  I’d be able to bike to the candy store, the library, my friend’s house.  And I was always told “you can do that when you older.”   And then there was a day when we asked if we could go bike somewhere… and my dad said older brother could, I couldn’t, and MY YOUNGER (developmentally delayed and nowhere near as responsible) brother could.  And that’s when “it’s because you are too young” became glaringly “because you are a girl.”  And I got smacked in the face with the fact that my father thought my younger brother, who I had to keep an eye on when we were out together because “he’s younger and it’s your responsibility” had more rights and freedom than I should have.  It sticks with you.  (And yes, I went crying to my mother about how “it’s not fair!” And she intervened with dad and got him to back off on that rule. But the damage was done.)

Selfish is an understatement, bro couldn’t care less about whether or not his wife and kids go hungry, not only is he literally taking their food off their plates he’s refusing to change this ugly side of himself. He cares more about being a big manly man than whether his daughters eat or not.

OP in the last story even offered to contribute food to the potluck and the money pool when they received an unsolicited email. Like what even is your brain, Jone?
And it would never have even occurred to me to not just state the bare truth to my boss when asked. If you need "protecting" from reality, maybe you shouldn't dish out what you can't take.

Story 4: What really gets me is it's not just that she messed up in the past and is now dealing with consequences, she's complaining about being lonely while actively sabotaging her new relationships like lady you are currently making the problem.