If they are charging you for new skills I can't see any problem with that, if you don't like it go elsewhere and pay more. Rule number 1 in business is do no favours, money is money especially when you training some one, no special treatment or preferences. If my partner can train me in skills I dont have, I would pay her, just like any other trainer, it is up to her if she took the money or not , after all it is their livelyhood.
If your spouse is charging you for training you, you can probably talk to him/her and request that she reduces the charges for you. You may also ask whether they can train you freely, considering that he/she is your spouse. You probably need to talk and help each other out.