I decided not to read the other posts, but just to give you my answer. It sounds like you are dealing on the weekends with what I deal with on a daily basis as a home childcare provider. We have five children in our care, ranging in ages from six years old, and in Kindergarten, meaning we have the added issue of getting that child to and from school each day, down to a six month old baby, with two toddlers and a pre-schooler in between. Believe it or not, childcare providers don't have all the answers, and we do struggle with the same type of issues that parents struggle with!
What I find most helpful is to, as much as possible, think things out ahead of time. I spend a bit of time in the morning getting all the bottles and the cereal dish for the baby set up so that all I have to do when she's hungry is add the water to the powdered formula or the cereal dish and mix it. We have her on a fairly routine nap schedule so we know approximately when she'll be down and that is time when we can give the other children more attention... though one of us is always there for them while the other takes care of her needs. We have established a nap routine with the baby so that one of her naps is during the afternoon nap time when the other children are resting too. That usually gives us at least two hours of free time where all we have to do is keep an eye and ear out for a waking child, but can do other things that we want to do... sometimes we even take turns having a little nap ourselves.
I also try to have meals at least planned ahead, if not partially prepared ahead. Using a crock pot, or making oven meals is a great help, because you can put the food in, set it, and let it cook without too much attention until you are ready to eat. Pre-cut your own salads and put them in a zip-lock type bag until ready to eat... or purchase a pre-made salad. Keep meals as simple as you can so you don't feel you are stuck in the kitchen all the time.
We do take our kiddos out when we do errands or for 'field trips'. It isn't always easy getting five young ones ready and in their seats in the vehicle ... much less the getting in and out and back in at our destination... but we manage to do it by working together. I have a small bag packed with the necessities for the baby... diapers, wipes, gloves (since I'm a child care provider rather than a parent), extra change of clothing, bibs, diaper cream, a bottle of hand sanitizer for me, tissues... you get the idea. I also keep three extra diapers for each of the toddlers. When it's time to go, I simply pop the extra bottles and cereal dish that have already been prepared for the day into that bag, and once we have had each of the older ones go to the bathroom, we're ready to go. My husband takes the older ones to the van and gets them fastened in while I bring out the baby in her carseat along with the bag. We're still in a stage of perfecting this process, but it's working out fairly well.
If you have grandparents, other relatives, or just good friends nearby who could take your children for a few hours one day, by all means get some time for just you and your husband to be together without the children for a brief time to rejuvenate.
I don't think I mentioned this yet, so I need to say, do be sure you and your husband have communicated... and continue to communicate... mutual needs so that you can plan to work together with him giving you some time to do your things while he watches the children and you give him some time to do his things while you watch the children.
Your situation isn't going to be just like ours, but I'm giving you this as an incentive to look at your own situation and see what you can do to help make things a bit easier.
Having said all this, know that things are still going to happen that make you feel like your weekends are chaotic. But if you can eliminate that as much as possible, you'll be better able to handle the rough times when they do come.
I just want to add this little bit more information about us. We are grandparents, 64 and 69 years of age. Several of our daycare children are also our grandchildren, and we often find that we take them on weekends too.... sometimes because their parents have need of childcare while they are doing something, but also sometimes because we simply choose to spend more time with them and plan something special. I'm not telling you this to give you the idea that we're some sort of super grandparents, but to encourage you that you can find a way to enjoy your weekends with your two children as well without feeling bogged down all the time.