You may not like what I'm about to say, but I do no favors by candy-coating this...
Suz T. is right, and very to the point. What you are doing, piling your emotional needs on your child (and others, from past posts) is unhealthy for both you and your son.
First, and I'm not saying this to be mean, but to be honest-- your son should not be your *entire world*. Where does that leave your husband? Where does that leave *you*? It seems like you are cultivating a dysfunctional, codependent relationship. "I do all these things for you and you don't want me and that makes me unhappy." Guess what? This is parenting. We do stuff for our kids ALL the freaking time and maybe half the time they are aware of it, and a small percent of the time they are actually and vocally grateful. Why? Because, if we are doing our job, our kids feel secure that we will love and provide for them and keep them safe. It is our job and not something we should expect affection and thanks in return for. Emotionally mature adults understand this and know that parenting is about creating a (hopefully wonderful) adult over a long period of time, not about having a child to love them back.
Love and affection happens when there is respect. At four and five and six, your son is seeking independence and some context for his social identity. He's strongly identifying with Daddy, which is NORMAL. He wants to do with/like Dad because Daddy is his role model.What you are interpreting as targeted rejection is likely more about this development. I would strongly recommend reading up on child development and the social and emotional development of children.
Getting into a power struggle with both your husband and your child only frustrates everyone. If I were in your shoes, I'd check with my husband when "I want daddy" works for him and when it doesn't. Your husband likes that his son wants to wait and do things with him. Who doesn't like being considered? I'm not saying the two of you don't need to be on the same page, but really-- does it have to be YOUR page, the one you dictated?
No one's perfect. When I find myself in conflict with my son and husband, I can usually, in a moment of soul-searching, figure out that this is about MY unmet needs and then can sort of find some objectivity. I would encourage you to also try to take a more objective stance.
I would also strongly suggest counseling for you and maybe your family. It seems that you feel the actions are meant to cause you direct pain. The people in your life are behaving in a quite usual manner, considering the circumstances. Your responses are rather insular-- they don't take into account the goodness or healthy motivations of the others. You are missing a whole part of the picture. Your son needs a strong mom growing up,not a mom who is emotionally devastated by normal child development.
And yes, if your in-laws are around and they are always helping to pay the bills, they are not going to see you as a capable, fully-formed adult. They see you as a dependent and may feel they can over-ride you and treat you as such. It would be good for you and your husband to figure out how you can be financially independent of them-- for everyone's sake.