If someone was flirting with your huaband would you point it out, or could that cause him to like her?

If he doesn't notice her flirting or liking him, or could you act like she's the way with all guys. I think it might fuel something if he knows a women likes him, I dont think he'd ever act on anything but who knows what a man is thibking about when he's not speaking or acting upon ? I just don't want my husband to think that our step sister in law likes him because well have to see her twice a year or so, and I don't know if think would make him like her or make him distance himself?