Your husband thinks your babysitter is hot. What do you do?

“We hired a new babysitter a few months ago and she’s been great so far. She’s 19 and our two daughters love her. My husband had a few friends over and I overheard him describing how hot she is and how he loves looking at her.
I felt sick hearing it but I haven’t said anything to him yet. I trust him, but it makes me uncomfortable knowing he thinks this.”