A., I feel how you feel!!!
I never cut my sons' hair ~ I just could not, just like you! My first son's hair was very thick and curling into beautiful big locks, he was walking around like a little angel and everybody loved it. So, his hair finally grew into a braid and that's what we were doing: braiding his hair. The second son liked Anton's braid and got one for himself also. Thus, they grew up. Anton NEVER cut his hair, you can see his braid even now.
Ivan decided in the 10th grade, and came to me: "Mom, please cut OFF my hair." I gave him a week for thinking, as long hair does not grow back fast,but he was positive he wants it cut.
Look at them now, there are notes on the Image:
and this is their decision, as this is their hair, their heads, their life.
Before they were old enough to make their decision,
I enjoyed seeing their happy childhood, and braiding their hair :)
when they were little,
neither one of them allowed anybody touching their head: only for me to brush and braid, it was allowed :). They just liked their space being safe.
so, while they were little, I let them BE naturally as they are, and when they grew elder, they made the decision. Our lucky part was that nobody interfered into it, their dad was absolutely fine with seeing his sons with long hair.
I know, I did not add any joy to your situation, A., I only want to tell you that YOU ARE a MOM and you feel right about your son's hair: he, personally, absolutely does not need a haircut, the one who needs it, seems to be your husband only, and it is definitely hard to convince him otherwise.
You can try to ask him to wait until your son will turn one year old, as his skin (and aura) is very sensitive, and you do not want to wave any metal objects around his head, and maybe by then your husband will be accustomed to seeing one curly boy... who knows? I wish you success, A.!