Help! My Boyfriend Is Cheating On Me. What Do I Do?

 when i first met my boyfriend i was already in a relationship. but he was determined to win me over. he couldn't do without seeing me. he'd call a dozen times a day.  my ex finally ended the relationship and i started going out with the present one. he was so sweet until he travelled out of the country. he wouldn't call me for weeks. when i call him he'd look for an excuse to get off the phone. he came back to Nigeria without telling me. when i found out i threatened to end it but he pleaded and i forgave him. but he has changed especially now that we r in different states. please your advice would really help.

 u broke with someone to be with another because he was persuative? dam! u so stupid ,