If you sing in public try singing songs that give support to the message you want to give.

"Thanks, but no Thanks" type songs.

Failing that try leaving books about the house like "Do-It-Yourself divorce".

It eases the pain for you both but at the end of the day "truth" is the only sure-fire way and it ain't gonna get any easier waiting. Practice the key points you want to say, but don't be too rigid with the delivery.

Here in the UK the counselling service is called "Relate" and you can go on your own. They will have insights on opening the subject with s/o.

Best of luck.