Here is what i decided.

I[28M] have been married to my wife [28f] for 2 years. we do not have kids and we do not plan to. I have a little sister [11f]. Due to the age gap , I am more like another father than a brother.

My father passed away from pancreatic cancer. There are 2 options for my sister: either I take her in or my uncle [dad’s brother] . So we asked her who she wanted and she chose me. Here is the problem, my wife and I decided that we did not want kids, So she does not want to adopt my sister especially since my uncle can. But my sister has no parents now and I want to make sure she is able to recover and be healthy and since she wants to be with me, I will not force her to be with our uncle. This is causing a lot of tension with my wife , things escalated and finally told her I am doing this whether she agrees or not, she can either accept it or we get divorced. We have not talked since then. What I can do in such situation?

Tl;dr dad died. I will adopt my sister. My wife does not want that. Tension is rising with my wife.

I talked with my wife again. She still refused as she does not want kids. So we basically decided to go our separate ways. She said you really are choosing your sister over me. I told her I do not want to go into this discussion again but if that what you want to hear then fine. Yes my sister takes the priority now, I am choosing her over you. This was our last conversation. I have been living with my sister for 1 week now. Being a single father-ish brother is definitely challenging but I am really enjoying it.

Tl;dr I got separated from my wife. I am taking care of my sister.