Haven't read the whole thread, so forgive me if I repeat anyway... I also have three DD1 6, DD2 4 1/2 and DS1 3 1/2. There is a sensible gap of two years between the first two and then only 11 months between the last two, so DD1 was 3yr 3 mnts when DS1 was born and DD2 was 11 months. It was shere hell for the first year to eighteen months.
It is getting a lot easier now we are out of the baby phase as DS1 was potty trained by christmas and around the same time we chucked the buggy. We now have no baby paraphanalia in the house - yipee. It's the little things that make it easier for example I know I can get them all out of the car without having to carry or hold each ones hand into the house because they won't just run off like a toddler would. Only DS can't do his own seat belt, so getting in the car is no longer a miltary operation. They all get themselves dressed.
When they get too much they are old enough to be told to go off to their rooms or the garden and play.
My personal top tip is to have the radio on in the kitchen, so that when you're cooking, washing etc you can't hear each and every winge and whine. Most of the time they are happily playing with each other, but whining at the same time - with the radio on I can hear if there's a disaster, but don't get wound up by the general goings on. Also my preference is Radio 4, so I feel like I'm actually using my brain (god forbid).
You are at the stage I was at about a year ago and I would honestly say that the difference is amazing - hold on it WILL get easier.
And another thing - Like you I have a DH who's not at home much, so I think that that precious nursery time is mine. Not for housework, for me to do what I want even if thats Fern and Phil, or reading a book. You must look after yourself or you'll go mad and you'll be a much better mum for it.