DH feeling stressed about having to perform

My DH is having a really hard time with us having sex every night or every other night. Last night after 1.5 hours, he was still unable to ejaculate. This is our first cycle TTC. I'm worried if we don't have success this round, how he'll be next round. Does anyone else's husband have this issue? He said it feels clinical and forced to him. I'm feeling frustrated by this, but am trying not to show it. Any advice would be great.