One of the main sexual problems men with diabetes can sometimes face is the inability to have an erection. Damage to the vascular system can impair blood flow. If the blood vessels aren’t functioning properly or if an artery is blocked, not enough blood will travel to the penis, making it difficult to get an erection.
Nerve function plays a role, too. If the brain isn't properly communicating with the nerves in the sexual organs, the body might not be able to shuttle blood there, impairing a man's ability to get an erection. The ability to keep an erection can also be affected, because the brain must communicate with the nerves to hold blood in the penis.
Fortunately, there are a number of treatment options available. Talk with your doctor about what treatment might be best for you.
Source: American Diabetes Association’s Diabetes Forecast