We have two kids and the yougest is now 2, and my wife is just getting back into shape. It takes time, and as you've noticed, the time goes by and you begin to think you're horrible and will be forever. Neither of these is true: who cares if you have some wobbly bits? I doubt if your OH does. Who looks like the airbrushed photos in magazines? NOBODY - not even the models themselves.
If you're over the weight you're comfortable with, you'll get it back down eventually, and in the meantime, just don't go squeezing yourself into clothes that are too tight - if you only have one great outfit, get something that fits, get some high quality undies and regularly get a bra fitting from a really good fitter, as your shape changes pretty much all the time.
If you add a little bit to your self-care routine every now and again you can start to pay yourself more attention. 3 children doesn't leave you much time, but if you spend an extra few minutes on yourself, they'll not miss it and you will feel better for it. It almost doesn't matter WHAT you do, it's the fact you're doing something thst will get you on the road to feeling better about yourself. It's so easy (well, not physically) to spend all your time on the family that you end up at the bottom of the heap. And while your OH can help, you need to devote some of YOUR energy to YOURSELF. It's not a sex thing - you can do that in the dark - but it's about making yourself an individual again, not just a milk-machine and nappy changer.