As we are Satmar chasidim, my father asked me not to buy a computer, and if I would, for sure not one with an internet connection. But, I’m married, and we decided that we do need it, so I bought it, but without telling him. Now, I feel very pressured every time he comes to hide it, not talk about it, etc. so I wanted to tell him.
My shaale is: Should I tell him (which might cause him tzaar, even if my decision is right), or just let it slip via the children, whenever this should happen, though this might insult him?
If the matter would slip out via the children, your father, as you mentioned, might be both insulted and distressed. Therefore, I think it would certainly be better to tell him. However, you can perhaps tell him in a way that will minimize the hurt. Rather than telling him, ask him: “Tatte, we decided that we need a computer. Perhaps you can advise us as to how we should use it best. Should we get educational software for the children? Should we record family activities on video, and let the children see them on the computer?” And so on. If you will make him a part of your decision, I think he would take it much better than if he were an ‘outsider’ to it.