Need some advice with anti depressants..

[Avgdaytonguy]

Ok so last night I was with my partner, and yeah we start having sex, all is good, he seems happy, Well I cum first and then Im helping him get off, but after like 5 mins of trying (and losing his erection) he yells in frustration and storms out of the room cussing. After talking with him he is on anti depressants that effect his ability to orgasm. He is really frustrated and says he doesnt want to talk and just wants to go to sleep, He doesnt want me to hold him/comfort him at all, he just wants to cool down. Throughout the night he seems better and we cuddle.
In the morning he says he is fine, he will get used to it, and he wants to deal with the problem himself. I keep trying to comfort him and he just says he is fine and doesnt want to talk about it really. And he says this doesnt change anything between us and it is okay.
How do I deal with this? I want nothing more than to help him. I told him it doesnt matter, I like to just seem him. Should I keep pressing him or just let it go? I have kind of suspected something was wrong because the past couple times I have stayed the night we dont have sex when normally we do, and when we do he just says he is just to tired to orgasm. Any advice please? Thank you