As Shakespeare said: "...out damned spot..." (I know its taken out of context).
What an intriguing question. It's difficult to answer, but I'll give it a whirl.
Activation of the Cowper's gland (or bulbourethral gland) is part of a dynamic feedback loop involved in sexual stimulation and fulfillment. It can be stimulated by visual cues and also by physical feedback such as stimulation of the penis. In other words, it has nerve connections to the central nervous system which are supposed to be involved in activating it. Yet, it is supposed to be quiescent when we are not aroused, but ready to become active when the feedback loop is activated. http://en.wikipedia.org/wiki/Bulbourethral_gland
First it must be asked: Are you absolutely sure that the Cowper's is the one that is misbehaving? I don't mean to embarrass you, but is it possible that damage to your urinary system during severe abuse has led to leakage of the urinary system? In other words, is it the slimy Cowper's secretion or is it urine that's leaking out? Or is there an infection involved here? What is the color of the leaking solution? Is it pus?
OK, if the answer to the above questions is that it is definitely Cowper's gland secretion, then why would it not assume its quiescent phase as it's supposed to? Assuming you are not partaking any of the drugs used in male stimulation now available on the market (viagra, etc.), then there is something going on with the feedback loop. So what would be activating the nervous system feedback loop? Is it DID? Is there a part of the nervous system which has been partitioned off and which is apparently not part of the usual system of activation? We know that DID has the power to act in this way. But is that what it is? Another question might be raised as to whether you sustained physical damage to that apparatus during the severe abuse you experienced. For instance, is there scar tissue exerting pressure on the nerve which is supposed to activate the system? And the last question is whether it's a body memory which is acting independently of the usual activating systems.
To get a better grasp of what's going on, try making mental notes as to whether the flow is always the same level or if it subsides at some times. This will give the best hint as to which if any of the 3 mechanisms I propose is being activated.