We have this problem but it is dh who loves the really hot chilli stuff. I like spicy myself and am partial to lime pickle (though probably not in sandwiches) but dh likes food much hotter than I do.
I do think though that dh's taste buds have been pretty much ruined by eating food that is SOOO hot all the time. He is also pretty addicted to it and has the same reaction when he goes without chilli for a couple of days as I do when I go without chocolate - i.e massive cravings.
DS (3.1 yrs) won't eat anything spicy. He's has a couple of bad experiences where he has eaten stuff of dh's plate while dh was not in the room or before he could be stopped and the tears, screaming and frantic clawing at his mouth were pretty traumatic!
The other day a friend of mine bought some paprika flavoured crisps for her daughter (2.5 yrs old) and ds wanted some. I didn't notice they were paprika flavoured and let him have some - well, he ate a couple but the look on his face as he realised it was 'spicy' was the screaming that ensued were quite spectacular.
Nowadays ds always asks 'is it spicy?' before eating anything off dh's plate. At least he asks, before he just grabbed
I do get slightly annoyed with dh though when he complains that a dish is bland.
Sometimes it is but sometimes it isn't, it is full of flavour, just that the flavour is subtle and dh always just smothers it with chilli sauce because he can't seem to taste anything else.
Sorry I don't have any answers for the child not eating chilli problem though, we tend to cook less spicy food and add chilli at the end as all of you already seem to do.
Dh does miss it though I know and will sometimes cook himself a very hot chilli (too hot even for me) on the rare occasion when he is on his own. I have the odd day when I crave a hot dish but generally I'm OK without.