Hi there and thanks for your question!
OK, thanks for that info!
The first thing I would do is to have your vet do a check on his urine. A good number of dogs with inappropriate urination actually have crystals in their bladder or a chronic infection or bladder stones. If this is the case then he can be treated medically.
If not, the best thing to fix this is strict crate training which you can read about here:
Most dogs will not urinate in the crate. If he does, you will need to put something such as a bunch of pillows in the crate to block off one end. Dogs will rarely urinate in an enclosed space. And then, he only comes out when it is time to go to the bathroom. If you do this for a few weeks and then gradually allow more and more free time this usually solves the problem.
Another thing you can do is to talk to your vet about a behavioural drug called clomicalm which often helps with problems like this.
The above is given for information only. Although I am a licensed veterinarian, I cannot legally prescribe medicines or diagnose your pet's condition without performing a physical exam. If you have concerns about your pet I would highly advise contacting your regular veterinarian.
This is a hard problem to solve without doing crate training! Especially if it has been going on for years.
The clomicalm is similar to an anti-depressant. It helps with anxiety which is often a cause for urine marking.
I have found some more info for you that may help with some other ideas on training for you:
I would also highly urge you to have his urine tested!