I totally understand. When I was married my XW was a SAHM, so she did the majority of the cooking, laundry, bill paying, and miscellaneous things like changing lightbulbs and getting tabs put on cars. I just had to crush it at work.
The problem is that splitting into two households creates a lot of redundancies both in work and in finances.
Financially there are two households to pay for, two electric bills, garbage bills, phone bills, internet bills, and surprisingly groceries seem to cost more individually as well.
Work wise there are two sets of lawns to mow, twice the number of bills to be paid, light bulbs to change, bathrooms to clean, etc.
Essentially you are working full time and running the house and parenting all at once. It's taking what used to be two jobs and requiring you to do both of them. There's a reason people used to stay married.
I got reprieve. My mother moved in with me and has helped me tremendously with the kids and with cooking and dishes. She helps with the kids laundry even. It has given me the chance to focus on my work in a time when I am really behind the 8 ball.
Without that luxury I don't know what to recommend. I was really exhausted for the first two years on my own. I just got through one day at a time, because I had to. I still feel that way with what's on my plate, but it has gotten a bit more manageable for me. Maybe you'll catch a lucky break at some point and it will get easier.
The only thing you can do for now is to really rest up when you have a break. When your son is with mom and you have a weekend to yourself, get some good recovery in. I have every other Saturday for myself. I try to make it count. For me it's playing pool. I even toyed with the idea of starting to smoke pot, it seemed like a potentially beneficial idea for every other Saturday. But then I figured I don't need to flirt with anything right now that could cause problems.
Also, I try to get a lot of sleep at night. I've been getting 8-9 hours. I need it. I'm sleeping more than I ever have. It's the only way I can get through.
So lots of sleep and lots of self care during your little breaks.
And most of all, suffer through because you have to, and feel free to vent away. We get it.
Me:38 XW:38 T:11 years M:8 years Kids: S14, D11, D7 BD/Move out day: 6/17/14, D final Dec 15