Maybe you're scared, worried you'll hurt the peace, or that the other person is not "emotionally mature" enough to handle it?
I believe that 99.999% of the time, you CAN have honest, vulnerable conversations with people that leave you both far better off. (Yes -- even the person you might be thinking "not them!" about right now.)
I, and many of my friends, use a "formula" to hold these conversations - and the results are generally miraculous.