Hey @am2 welcome to the forum and a great opening question
Firstly I don’t have any direct experience of this topic but others here have offered great advice already.
However I will attempt to help out so I will add my two-pennies-worth by suggesting you get your OH to wear her pantyhose as part of a foreplay session etc and tell her how great it feels whilst you massage her.
You could then maybe suggest that you wouldn’t mind joining in the experiencing of wearing pantyhose/tights, tell your OH that you’d love to try on a pair and say you’ve always wondered what it would feel like and see if they are keen?
From my perspective I have just tried on my first pair of red tights (I have a thing for 
) I bought over the weekend to see what the experience would be like and, as I said in a different topic ( Lingerie and outfits for men - #6 by Mid-50s_kiwi) OMG I really enjoyed whole the experience especially the look and how it made me feel so now I’m in a similar situation as you of working out how to raise this topic with my OH especially when she isn’t into kink 
Good luck 
and do let us all know how you get on and any advice you might be able to offer others in a similar situation
