Is realising that you get to choose. You get to choose who you spend time with and the relationships you invest in. You get to choose how you spend your money and how you grow it. You get to choose whether you want to stay in this job, or pick another one. You get to choose how you're going to feel about this current situation.
The fastest way to happiness is to choose to be happy first and then take actions that bring you closer to that choice. The fastest way to feel unhappy is to feel like you're a victim of what life is throwing at you. The biggest shift you'll ever have is realising that the only person who is responsible for your happiness is you.
It's not his fault, her bitchiness, their high expectations or your parents lack of preparing you for the world. You are so much more powerful than those stories.
Wipe the slate clean, declutter, let shit go. Then get to work on getting happy.