I sorry but i believe you are only postponing the pain of losing him. You love him, he doesn't love you. Do you have a life outside this guy? If you know that he will leave you as soon as he finds another girl that interests him, you are only asking for pain by being his substitue. It would be best to cut ties with him and move on. I know it will be painful since you love him but you need to open yourself up for someone who might come along and appreciate you and can love you the way you deserved to be loved. Just my 2 cents.
Gayle