YANBU . My friend kicked her XH out after years of trying to make it work. He was a workaholic and was never home with the DC. Now he has them one night a week and one day a weekend and spends far more time with them than he did when they were married. He would never go on holiday before, but now he takes them away at least once a year.
My XH however, did usually see DD every day, despite working odd hours, but now he only sees her EOW and I fear that will become less now that he has moved 2.5 hours away from her or if his gf has a baby.
However YABU, having a workaholic DH is not the same as being a single parent. You do have somebody to help make decisions, to help pay the bills and who is there for you. You have somebody to share school reports with, and to talk about your day with.
I get friends who envy my lifestyle of having EOW to myself. However I envy their family life. I would rather be sharing weekends and evenings with a DH and my child, than have EOW on my own. I usually end up working just because all my friends are busy with their families.
A friend said a few weeks ago, oh you are out once a fortnight, I wish I could do that and I replied that I would rather be home with my DH and child, but I don't have a choice.
I think in your situation, you need to ask your DH to do something with DS, just the two of them maybe once a month, or EOW, just for a few hours. Take him swimming, or to the park, or whatever, but just something that they do together, just them.
XH used to take DD to the park while I cooked lunch, or play in the garden with her while I cooked tea, and he used to give her breakfast every morning while I was in the shower. just little things, but she used to love spending time with him. She was a proper daddy's girl before he left.