How to have a serious conversation without a fight?

Needing to speak to my husband about our relationship. In unhappy. He's treating me poorly. We haven't been compatible and I know he's lying about something. I don't want to be confrontational and I don't want to have a blow up argument. I'm thinking about doing this tonight after the kids are in bed because he and I haven't had any arguments today so I'm hoping that will make him less hostile. Usually if I speak about these things he instantly gets very hostile upset and yells or blames me or spins it to me and won't listen to what I'm saying about him.

I want to tell him how I feel and be honest and tell him I'm willing to keep working in this if he goes to therapy and gets help. I don't want him to assume I want to end things but I know he will lash out like that. Any advice? My therapist told me to bring it up when we are not fighting and to be very direct and emotionless. Any other tips for me ?