Why does Hyde commit suicide?

Basically, Hyde kills himself to permanently rid of anything Jekyll inside of him.

Jekyll knew that Hyde was taking over due to the random times that he turned into Hyde. He knew that Hyde had a fear of being hanged for the crimes and therefore killed himself. Part of him does feel sorrow for Hyde in the quote "I find it in my heart to pity him" but Jekyll knows that Hyde is getting out of control and has to rid the world of him.