Do you think it's ok for a 5 yo boy and girl to kiss each other? And to talk about who they are in love with and who they are going to marry?
I see this as fairly innocent (although I don't much like it when adults join in or encourage the talk with "But I thought you were going to marry so and so" kind of comments).
But my DH doesn't like it at all and thinks they shouldn't be kissing. He was brought up in an environment where children were emulating adult sexual behaviours (with each other) from a very early age and he didn't realise how inappropriate this was until he was grown up. He wants to protect our DC from the same.
It's causing a rift.