She's Not Our Daughter!

A few years ago, my ex-boyfriend, who I broke up with after our one-night stand, came to visit me as a duke. He said he regretted abandoning me.What are you talking about? What’s there to regret when we’ve split up with ease?Also, I think he even misunderstood my sister’s daughter for ours.“I had no idea. I didn’t know you were raising our child alone.”What is this situation?Just then, my niece, who hid herself behind my back, stuck her tongue out at him.“I hate you, you’re a bad guy who abandoned us. Go away!”He staggered in a shocked manner.No, he didn’t abandon you.And I’m not your mother