Husband is pressured to "perform" at the optimal times

Hi everyone,
​First time discussion poster, long time lurker.  :)
​My husband has trouble completing the act when it "matters the most". I try to be supportive and he is so ashamed. He's not very sexual overall so jumping in the sack on demand is really difficult. I'm not upset w him having performance issues, but it's so frustrating that he lets the fear overcome him and not even try again the next day. I feel terrible and I  know my frustration hurts his feelings. Any suggestions? Thanks all.