Oh no, not on my “old feet” at all. I’ve had to change how I work, how I keep fitness levels where I’m happy with them, how I manage the house and my kids are teenagers now.
What that many for me was accepting that my 6.00am swim wouldn’t happen but I could carve out time in my day for a weights routine. I work from home for a very flexible employer, sometimes work happens at very odd times bit it all gets done. I’ve massively decluttered the house so it’s easier to keep up with and I have a cleaner.
The most important bit though is my DH is my backstop. He picks up the things I can’t, will flex to do the school run, get the kids up and out if I need to be away, does at least 50% of cooking and cleaning.
While your DH works away, I’m sure he’s home enough to pick up the slack, which he needs to do. None of this tired from travelling, can’t possibly take a day when the kids are ill nonsense. If you weren’t there he’d need to find a way.
Your child has two parents, you both need to keep things covered, his big job doesn’t excuse him from parenting and no, is not be having a second child until he properly parents the one he’s got.