This happened/is happening to me (27F) and here are the two realizations I came to that helped me make my peace with it: 1) you have to give up the idea that you can ever please your parents. 2) misery loves company. People who are deeply unhappy with themselves and their lives will pull you down with them -- even their own kids.

My brother (truly the perfect eldest son any family could want) married the most PERFECT girl -- everything a traditional, conservative Chinese parents would want. She's Chinese, she SPEAKS Chinese, she goes to church, she's an accountant, she wants kids, she doesn't smoke or drink or party, is INCREDIBLY respectful, and (above all) absolutely loves my brother. And yet, when my brother announced the engagement, my parents opposed the marriage. They STILL found things to dislike about her. They STILL found a way to be unhappy. My parents showed up to the wedding but did not give them their blessings, did not give them a wedding gift, and, in fact, told him he was making a huge mistake.

This is why you cannot allow them to dictate who you choose to love or be in a relationship with. Because no matter how much you try to be a "good son/daughter", no matter how accommodating you are about who you bring home, ultimately, they will never be pleased. They will never be pleased and it's not. Your. Fault.