can't get hard

my boyfriend and I have been together for two years. we've always had the problem where he couldn't get hard or would cum quickly. He got put on anxiety medicine to help calm his anxiety down. He changed jobs which this one is less stressful. sex was really good for a few weeks and now tonight for the third time sex isn't happening. he either cums quickly or just doesn't get hard at all. I just don't know what to do