Reconnecting with my old situationship after recent breakup

Not sure what to do because me (22F) and my past situationship from college (22M) are talking again because my 10-month relationship ended. I’ve been feeling super relieved since we broke up because it just wasn’t working anymore. Anyways, I had this situationship off and on for nearly two years but stopped because I met my now ex-boyfriend. The situationship was a roller coaster mainly because each of us had different priorities at various points but we always remained in good contact as friends. Now that I’m single again, we have been communicating everyday. Unfortunately he moved back home across the country for law school and has no plans of leaving afterwards. I on the other hand am interested in finding someone new nearby to slowly build a connection with because my ex was garbage. For now, I am chatting with my old situationship but feel bad for using him as a “placeholder” until I meet someone I want to become serious with. I know the old situationship is a good person and would understand if I found a better fit but I just wish we could be together at last