I think back to my mother with five kids, all those meetings, slavement er service and wonder how the heck she didn't go mental and I respect her alot for being as patient as she was. It makes me appreciate my kids so much more though, they get their own snacks, juice, go out and play outside, etc. I can have coffee without having someone climbing all over me! I promise to all those struggling with toddlers, it DOES get easier and the pay off is enjoying watching your tiring toddler turn into a unique individual who you can laugh with and enjoy for who they are. I do think teaching them that Mommy needs her "time out" at 3 or 4 is very important, to teach them some independance instead of having a say..6 year old who relys on you to do everything for them ( and believe me, I've seen that too).
My partner has two, 2 and 4, (which was a big adjustment, going back to the sleepless nights) it caused some friction with my partner and I at first, our different parenting styles, lol. We have them 2 to 3 days a week and I am wiped when they go home, as much as I adore them.His oldest insisted on having someone still wipe her bum (and they would!), I wouldnt' do that with mine once they were potty trained (completely of course), I taught them it was their job to do that! But he's come around and she now does alot of things herself that she didn't do before because she was told she "couldn't" or wasn't "old enough". If you teach them independance while giving them lots of love it will benefit mom and dad and the kids in question. Not to mention keep you sane, hehe.
Nothing worse for a parent than a child who needs to be entertained constantly and is incapable of entertaining themselves at all, IMO. Now, my two are a breeze to take care of, they get cuddles and hugs and the attention they need without draining me of the time alone I need. Hang in there.