First of all, it is importan to know if when you left they agreed to wait, or leave things each on their own.
Second, your partner failed to be honest, to tell you that he was dating someone else, to clarify that he would not wait for you. But by not doing so, he only realizes that she isn't a good person, therefore you shouldn't suffer for him. Life is responsible for giving each one what corresponds to him, she was not for you, she did not care about the 7 years together, so do not feel bad, give yourself your time, heal inside and the right person will arrive without you looking for her.