My husband and I have been married almost 10 years. He has been having pain in his testicles and

My husband and I have been married almost ten years. He has been having pain in one of his testicles, pain in his lower abdomen (possibly his bladder? ) difficutly urinating and the flow is very weak. Also he cannot ejaculate like before and two erections during intercourse is the max for him now, (wasnt unusal for him to either maintain his erection through four or five orgasims, or to achieve a new erection within minutes of orgasim in the recent past). This pain and urinating problem started about 5-6 months ago. He went to our doctor and he said "drink more water or sports drinks." Our doctor also checked for an enlarged prostate, which he said was fine. He drank additional fluids and didnt complain anymore until this past week. Now he says the symptoms are severe and it is affecting our sex life. Also he is only 28 and up until recently like I said we were very sexually active. He went back to the doctor and he said he has testitis? The doctor prescribed him two weeks worth of antibiotics, and one week in, he is not feeling any better. I had some reason to suspect him of cheating in the past six to eight months, but he says no way. Anyways what I have read about testitis is that a man usually has this problem after a STD and or mulitple partners.

What I would like to know is first have any of you experienced anything like this and if it was testitis was it related to a STD? If it wasnt what else might be causing his symptoms? I am very worried, he scared me the other night when he said " I hope I dont have bladder cancer," and then went on to talk about all the pain he has been having. I believe and I told him if it was bladder cancer I would think he would have blood in his urine. Any replies would be appreciated and I am also wondering if it sounds like a STD, should I get tested? and if so what would I ask my doctor to test me for? Thanks very much !