hey!
even though it could be a serious problem that needs to be treated my a psycologist or any kind of doctor, yo might also consider the fact that comunication is not everything all the time, try relaxing and letting him enjoy the moment by not focusing just in him, if he cant get an orgasm it could also be the fact he knows you are really expecting that to happen. Let him relax, if he werent enjoying he just would have sex with you, let him stop thinking about it and next time you 2 have sex focus a little bit more on what you feel that on what he is feeling, sounds selfish but its like that phrase "i wont wash the dishes i mama tells me to do it". let him look for his own pleassure he might get excited about something that was spontaneous and from that momment and on be able to orgasm.