I want to look after my grandchild once a week but he says this will affect our work and is not happy for me to do it despite me saying i will work an extra day at the weekend. was what the OP said. Unless he really is a controlling man, he must have his reasons for saying this but without detail, how could we know.
If I spend more than a few hours a week with my grandchild he says my life revolves around her
Yes, on the face of it, it sounds like jealousy. However, we don't know how often the OP is spending working time doing things related to her grandchild, like texting, looking at pictures, video's, etc so to her husband it might seem excessive when you put it altogether. My sister's couple of hours works on NHS time and is invariably far more so there may be a mismatch of stories. On the other hand, if it really is a couple of hours a week, that sounds quite reasonable to me.