Soon I'm coming home to a empty home and my mom will try to hide from me my dad's mistress that she will be hiding in my room

I just dont understand why I'm the one that has to suffer for being a hideous monstrosity. Why was I born like this? What did i ever do to deserve this. Here I am working hard to be of service to people and make a good life for myself and my family only for my dad to use his money to fuck a young relatively good looking woman because my mom can't satisfy his needs. My mom is a great woman btw. I feel bad for her but the only way I can deal with this is that I cope by hating her for bringing me into this world. Why should I care about these people that don't care about me? I cut my teeth on these people, fed with their milk, protected by their love, and this is the thanks I get? I dont expect my dad to love me or anything but I just wish he could do the minimum and not humiliate my mom like this.