@Fatty91
OP, I find your thread really odd, to the point I wonder if it is real because of the weird drip feeds that you seem to say so flippantly. There are many issues here:
You seem to hold an enormous amount of worth and validation on appearance and weight. "Perfection" to you is a 40yr old mother in a crop top. I think it's ok to feel a bit rubbish in the period after childbirth, when everything is transforming and not how it was before, but would you really suddenly feel perfect if you could walk around showing your stomach? How about when your child sleeps through the night, or when you've nailed bathtime, first smiles, words, steps...
I think you need to take a step back and look at why this doesn't seem to be as important as being "flabby" or not.
Even your username "fatty" that you've chosen for yourself, out of every word you could have selected. You seem to identify as your weight.
Your partner sounds like a dickhead. That's a separate issue. The prostitute comment, if it was a one off, is thoughtless and unkind, and probably a reflection of exasperation and inconsideration, rather than him being a truly evil person. Still not ok that he said it, what I mean is, doubtful he actually meant it, and more of a stupid heat of the moment comment by a man frustrated in a sexless marriage - too blinkered to see the valid reasoning why.
It will sound harsh, but I'm just being direct with you now - you say you are so miserable and jealous of slimmer people, but acknowledge you are doing nothing about it. Well, change that. Go for a walk with the pram. Just a little exercise like that will improve your mental state and your physical state. It's surprising how much you can initially lose with a little effort. It gets harder to lose the very final bits, but the initial loss is much easier. Every little helps.
For what it's worth, I'm a "perfect" mum, to you. My twins are fantastic, but feral, and frankly should be potty trained by now and that's a failing on my part. They don't behave in restaurants so we never get to enjoy a family meal out. My jealousy comes from mothers whose children are walking nicely beside them, and not whinging to be carried and plonking themselves on the floor. From mothers whose children sit and eat their food nicely in a restaurant. From mothers who only have one at a a time to potty train, and don't have to carry a massive changing bag for two everywhere they go. From mothers who can twirl their DD's hair into lovely bows and plaits, while mine yells "ouch, get off" furiously if I have the audacity to even brush it, and so walks round looking like a tiny Miriam Margoyles. I'm jealous of the mothers who have mum friends and a social life with their children, because they only have one toddler, who can sit on mummy's lap, while she drinks her tea and chats. Whereas all I have is, as soon as they see their little friend sitting on their mum's lap, is them both wanting to sit on mine: "MY turn to sit there! Get off, my turn!" and I can hear nothing over the bustle, which inevitably turns to tears when both are told to stop it, and then I can't comfort both, properly, simultaneously. I've lost count of the times I've just looked at a mother enjoying time with her child, and relaxing in a social setting, and I get this inner twinge of "oooh, you smug bastard, with your free hand."
Can you tick off any of those things I mentioned? Then I'm jealous of you. Difference is, I can't do anything at the moment to change the fact I have two toddlers, but one pair of hands, so I take a breath and tell myself it's not forever and I'm riding it out. You can, however, do something about what bothers you. Your baby is nearly 2 months old, and is your third. You know what you're doing, so can absolutely start taking a little exercise, or watching your food intake. If something makes you that miserable, and you have the ability to change it, then don't make excuses, be accountable to yourself and take the first step. Take some time to understand why weight is such an overriding part of your life, and maybe work on that too.
All the best OP xx