Would it perhaps be better if your protagonist was a man child running from marriage? The kick in the nuts and a look at his future alone might be the prompt he needs to kick his life into gear and grow up. The adult version of his girlfriends kid could make the man child realise he’s just that. As it stands now, it sounds like your protagonist already has his life in check – he’s settling down and about to assume the role of a father.

Take it back a few steps to build to this – well, that’s my suggestion anyway.

Good luck

Hi,

If it was me (which it’s not) I’d perhaps have him ditch his date. Say he’s going to the bathroom but really leave because he’s not comfortable trying new things – hence passing on love out of fear. He could then escape out of the theatre into a back alley and perhaps be picked up by a taxi driver who drives him to an alternate version of his current reality. Perhaps he goes home, goes to sleep only to find when he wakes to go to work everyone is signing – you could have some pretty funny songs relating to accounting as it would be a stark contrast to the dull stereotype.

Things you’d need to focus on though are how going to this new world helps him overcome whatever flaw you’re assigning him and how the alternate world comes about. Does he get stuck in some sort of wild storm? In essence what you’re talking about is a form of magic – is it a super natural occurrence that sends him into an alternate force or is someone targeting your protagonist?

I think making the date send him to the alternate reality limits you. If she is aware, the magic will go. If however they were work colleagues, it would provide opportunity for him to fall in love with her in his alternate world without her being aware that he is on a journey (if that makes sense)

Good luck