Saying what you’re afraid to say works out really well. Put it out there. Say what you’re not clear about. The people who love you will support those feelings about 85% of the time exactly the way you’d hope they would. The other percentages of the time will hurt 85% less than you think it will. And isn’t 85% less pain worth 100% better communication.
Also, sometimes this ends up in divorce.
Then again, evolution doomed your monogamy to begin with.