[Ettiominiw]

If a spouse insists that you do not do a sunnah (note sunnah and not fardh) act whatever that is, then to keep the peace you probably shouldn't do that particular act, but increase your observance of other sunnahs to make up for it (there are many forgotten sunnahs too that you can revive). So if your wife is insisting you don't wear sunnah clothing, to keep the peace don't wear it, but start praying all sunnahs and acting on all the other sunnahs of the Prophet SAW, such as giving sadaqah, treating orphans with kindness, opening your house to guests, praying tahajjud regularly, doing istighfar regularly etc etc.