Scott didn't need to be a scientist (which he wasn't) to see what was going on here. It'd taken him a minute, sure. But now it was plain as day right in front of his face. Ari clearly didn't like Sarah, and it was obvious that she was blatantly being judgmental. He loved his wife, but there were always going to be things he didn't like about her. Sadly, this was one of them.
"Ari, honey," he started, quietly. "Maybe we should let the kids talk alone for a bit." He leaned in close so only she could hear him and whispered, "I think you're embarrassing him." Or scaring Sarah. Either way. It needed to stop.