To put things in context, very fast : my mother left my father and I when I was a baby, letting him providing for us. Then the day my father remarried, had children and his wife made my life miserable until I decided to live with my grandparents.

My father and I haven't had a good relationship since then, and even before. I always considered him spineless and he resented me for what my mother did. Still, he helped me financially for my studies, and gave me a nest egg when I was adult. Mainly for fiscal optimization, but hey. The nest egg was supposed to be for everything besides the studies but I never touched it, preferring to work.

We saw each other during family events, but have no more affinities. I just see the ghost of someone I once liked. He lives a wealthy life, or so it seems, and I share none of his interests. He shares none of mine either.

Fast forward many many years, and here we are.

Two events degraded the already low esteem I had of him.

First, his daughter, my half-sister, recently started to open herself to the world, seeing people outside of her close family circles, and especially dating a guy that her mother did not approve. Indeed she was already shipped with some other boy, thus her mother started to make my half-sister's life miserable too. When consulted about it, my father insisted that he would stay neutral in this matter. (Just like he was neutral about me years earlier, allowing his wife to lie and manipulate to her heart's content.)

Second, I recently had a child, and wanted to start investing in a home for my wife, my kid an I. To do so, I took the aforementionned nest egg into account. So I was surprised when I learned that my father had liquidated it to pay his taxes and debts.

While he finally accepted to give this money back after a heated conversation (claiming that the money has always been his and that I should have taken it before if I needed it, and "Welcome to life"), I am still disgusted by the contrast between the high life he's living, his participation (even presidency) in a charity club, the money his spends in futilities with his wife and other son, and the fact that he took money that he claimed was mine in my back. The throwback to my previous situation with my half-sister doesn't help to appreciate him.

Thus I decided that this man and his wife had nothing of value to give to my family and especially my son. I especially don't want my stepmother to see him and I see him and her as a single entity at this point, so be it. Actually this money matter was a relief, because it gave me a solid reason to prevent them from reaching another kid.

Not sure if I am an ingrateful asshole, overprotective, right or a little bit of both.