Did i make a mistake?

hey am feeling down nearly been with my bf for about a month but before we got together he had really strong feelings for this other l but he started not to talk her .but then he got into me as we went out a few nights a week and we finally got together but a few nights ago this l started to tex him and it was the girl who he had strong feelings for before but he tells me he loves me and he would do anything for and were really close but i dont know if this l is trying to get him to be her bf what shall i do :(