oldkentroad - all of the many conditions and tests mentioned above are all possibilities. Another possibility is bladder stones.
However, as one urolgy consulant confessed to me - TBH, urology is very much guess work and it can be extremely difficult to pin down specific conditions. All bladder conditions present with the same basic symptom - frequency of the desire to urinate and constant discomfort. Indeed, I have been through every single test and have every single diagnosis described above. There is no indignity I do not know. At least I understand a little of what DW had to go through while pregant now.
My experience was not to discount any possible diagnosis or cure and to press very hard to get all the tests done in short order. Unfortunately, it sounds like your DHs GP has already dismissed prostate as a possibility - presumably because DH is not the right age for it. The other thing I found was that the symptoms have the capacity to destroy your life and doctors do not do anythng to help you get through life while they do their tests.
Whatever it turns out to be, and it can take years to find out, the most distressing thing for me was the length of time it took and the impact of the symptoms on my life. Believing it to be stress because that is what doctors kept telling me I gave up my career. In fact I was stressed by the condition itself. The physical condition fed back into stress. I agree with Bonsoir - this sounds like a physical condition and I quiet understand it is now feeding back into a psychological condition of nervousness about being 'caught short' and general depression and stress. It is hard to separate the physical and mental impacts.
I often found I went through a battery of tests and then when they came back negative the GP/consultant lost interest. I sort of got the feeling sometimes that they thought 'its all in your mind, just stop being silly' was their diagnosis. I know now that it is a physical chronic condition but it did not help being told it was in my mind. I felt like it was being told it was my fault and I was just making it up.
Being able to 'hang on' at home but not at work is avery familiar story to me. It may be due to work stress but more likely it may just be the fear of embarrasing oneself in public that is most unbearable but that disappears at home so making the condition bearable and ignorable while say watching TV is my experience even though the physical pain was/is always there.
The sensation of contantly needing to use the toilet in a meeting, needing to get off a bus, being deperate to use the toilet during landing procedure on a plane, missing children's plays, not wanting to go to go on long car journeys. These are all very familiar stories to me.
Yes please do get DH some of those pants. It will transform his life by giving him confidence while he finds a cure. Please do not let it destroy his life and career. Being able to bear the pain and discomfort is one thing but constantly feeling embarrased, stressed and curtailing your life is really something that can be dealt with and only at 70 pence a day I think it is worth it. No one will be able to see he is wearing them and I do not let my DW see me wearing them so she does not feel differently about me.