What does exercise really do for a person who has diabetes besides maintain your weight? I do cardio 3x a week and strength training 2x a week.

Quite a lot. There's a common mantra among physicians that "exercise equals insulin." muscles use glucose to generate energy used to contract, burning glycogen stores, and drawing glucose out of the blood. This allows the body to maintain blood glucose levels without adding insulin. It promotes weight loss, further reducing Insulin resistance. Maintaining normal glucose protects the eyes, kidneys and nerves.
Exercise & diabetes. Maintaining healthy weight is definitely one of the most important things in the management of type 2 diabetes. In addition, exercise makes your body more sensitive to insulin, possibly reducing the need for medications and insulin. It is beneficial for your cardiovascular health, lowering blood pressure, lowering bad cholesterol, increasing good cholesterol, decreasing stress and improving mood.
Heart Health. Diabetes is a risk factor for heart disease. Aerobic exercise is very important to help counter this risk factor and maintain a healthy heart. Keep up the good work and wishing you'all the best.
Numerous. Cardiovascular fitness in general and cardiac protection from diabetes in particular, psychological well-being, blood pressure control, cholesterol improvement, increased Insulin receptor sensitivity, improved glycemic control...