I don't engage in over the top PDA, but I am 39 and my BF is 47 (dating 1.5 years) and at our lunch with his parents and kids today we would randomly touch each other, not because we were insecure or needing to mark territory, but because we love each other and it just kinda happens. I think some people are simply more touchy feely than others maybe? And like I said, my parents do the same thing. My sister and her husband (married almost 14 years) do too. It's good to see, in my opinion, for kids too.