My (37M) wife (38F) kept encouraging our son (14M) to meet new friends since we moved. He's become good friends with the girl next door (14F) and my wife is upset.

I met my wife at college. I've been with for 17 years and married for 13. We have three children together. Wendy (9F), Nick (9M) and Joey (14M). My wife got a great career opportunity to join a big legal firm. The only problem was we'd need to move to Boston. It was a hard conversation to have with Joey because he ******. You know how teenagers are when you give them life changing news. He didn't take it well at all and he didn't talk to us for a week. Wendy and Nick then started to act like Joey because he's the older brother. It was was a big ordeal we had to deal with.
When we first got to Boston 2 months ago, Joey wasn't coping well with the change. He kept moaning about everything. He hated everything and everyone. A month ago his attitude completely changed. He started coming home late saying he was at a friend's house. He started going out on Saturday and Sundays to next door. Before I knew there was this girl, Kelsey, was walking into our house with Joey. They're always at either our house or next door. They walk home from school. They do things together.
Last night my wife had a meltdown before we went to bed. She burst into tears because she thinks the two of them are dating, and she's terrified Joey is going to get this girl pregnant. I don't get the sense that they're dating. They just seem like good friends. She's been doing things before this like going to Joey's room to check up on them. She's just become paranoid. This morning she asked if he and Kelsey couldn't do homework together. He asked why and she gave him some weird answer looking at me to say something.
I tried talking to her about this and she's just fixated on the fact that they're teenagers and she knows what they're like.
TL;DR: How do I get my wife to stop being so weird about our sons first friend since we moved?


Source.