I agree with Sophocleese. If you're not use to doing so, get comfortable with the song.

I usually walk a lot of places. There are still lots of places in town where you can sing at the top of your voice, if you wish, and not irritate people. So, if you need to practice, away from the wifey, start taking long walks. Say near the waterfront, or along a railroad track. Once you're familiar with the songs you want to sing, and you are comfortable singing them out loud, you should do fine.