The way the waltz alternates, starting with different foot each 1 2 3 can feel a bit strange...if you are already OK with some types of dancing, does it help to think of it in 'lumps' of 6? L R together R L together, then start again? ( I am not sure if it matters which you start with, as long as you and your wife do opposite to each other!)
Can you find a couple you know who can already waltz and swap partners...purely for the dance, I mean! Most dance teachers would give you a one-off private lesson, I would have thought, if you really are desperate and don't mind paying for a single lesson, or maybe they would suggest a couple of their pupils, who would consider a cheaper version of a lesson?
When I first learnt, you started off by going around in a big circle so you didn't have to worry about turns and things.