The only way that dating a new person would make you forget the one you love is if the new person is WAY better. If by comparison one realises that the old relationship was really crap.
However, the thing which really bothers me is seeing someone being used as a salve to try and recover from a broken heart. If someone is using you this way, then you deserve way better. And if you are using someone else, then stop it.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.