Aaaahhhh, the wonderful game of lets make daddy feel rejected!
Sounds like this is what it is so I'd say your best bet is not to join in, just let mum do the bedtime routine etc for now without any suggestion that dad should do it or be bothered by not being allowed too and be a right spoilsport and ruin all his fun.
Thanks for your comments, have already decided it's better to not have the episodes.
My only concern is Dad wants to be involved and I worry about their relationship suffering??
Is this a phase and should I not worry so much?