deinetwegen: polite form?
deinetwegen: can this word only be used for friends? Is there a polite/formal form? (I tried looking up Ihretwegen but it seems not to exist) :(
The polite form of "deinetwegen" is "Ihretwegen" (derived from the formal "Sie"). The word does exist; you constructed it correctly. It's in the LEO dictionary: https://dict.leo.org/german-english/ihretwegen
Someone who wants to curry favor with the person they are speaking to could say, after doing a good deed:
"Das habe ich nur Ihretwegen getan!"
And yes, you can use "deinetwegen" among friends. For example:
Du hast dich schon wieder verspätet! Deinetwegen verpassen wir den Zug!