Absolutely no problem! As @magigi says, what spoils everything is the man's inferiority complex - 90% of the time. There are some questions your [caring] wife/girlfriend will always ask about your whereabouts, habits, buddies, how you spend your time/money etc. When the wife/girlfriend is earning less, men seem to tolerate/understand/deal with such scenarios better. When the wife/girlfriend is earning far much more than the hubby/boyfi then it's a totally different story - everything is misconstrued. It's all psychological and it's the men more at fault.
I actually believe men should do all they can to help the women in their lives be more successful. If she wants to go for further studies, assist with the fee, pick her up after [evening] classes, fill in the gaps she lives at home - be the primary parent [assist kids with homework etc.] as she studies etc. If your main hold on your wife/girlfriend is your money, then you are living a very sad life indeed.
Never count on making a good sale. Have the purchase price be so attractive that even a mediocre sale gives good returns.