This other couple in our group does too many pda’s. Nobody has confronted them but it makes all of us very uncomfortable. What do we say? We don’t want them to leave the group but we do want them to stop.
I would say exactly what you just said in your question. "We don't want you to leave the group, but your PDA behavior makes us all very uncomfortable. We hope you will be able to remain in the group by respecting our wishes." That should pretty much nail your message down. If they continue, they made themselves history.