I’ve always tried to be there for Lila, my stepdaughter. When she became a young mother, I jumped in without hesitation: late nights, filthy diapers, doctor’s visits. I was her back-up, no questions asked.

Last month, she requested me to babysit her child during a weekend “wellness retreat.” I cleared my schedule. But two days before, I received a text that altered everything. It was Lila, in a group chat, bragging about traveling out to meet a man she’d been covertly dating since her pregnancy.

I was astonished, but then I saw the guy’s name and froze: he was my nephew. My sister’s son. We had been apart for years but had recently reconnected. And then it occurred to me: the baby Lila is raising may not be her boyfriend’s. I didn’t say anything.

I let her show up on Friday, baby in tow. I grinned and replied, “Actually, I will not be babysitting. But your partner might want to read the message you sent.” I then handed her a printed copy of the chat and shut the door. The infant cried. She did not. She just stood there, silently. But now I have no idea what to do. Should I say anything? Should I tell anyone? Should I just mind my own business and let things go?