Why is communication so hard in relationships?

I have not had a problem communicating in a relationship in so long but this one has really done a number on me. My s/o totally clams up and gives the silent treatment whenever he doesn’t know how to respond or thinks he has hurt my feelings. It is so frustrating that I could just scream! He cannot deal with emotions at all and I do not understand how you can be 56 years old and not know how to talk about what you are feeling. Really?? What the hell am I to do? I am so sick of this.