Omg its not impolite. You're going to talk about being polite on the phone with russians? get real. Half the time you ask for somebody, and if they arnt home they just say "No" and hang up.

"Some Russian - дома?" is perfectly fine for 2 kids calling each others boyfriend / girlfriend.

Now if you were calling your boss' wife about a meeting and you needed to talk to your boss to set something up then yea sure maybe you'd show her respect when calling but if its your boyfriend? Who cares?.