Getting back with an ex but with someone new?

My ex and I broke up a few months ago, but we remained in contact and still talk.

Since then, I began seeing someone new. The new guy is incredible and treats me better than my ex ever did, but i feel like something is missing from our relationship and I feel like it's because I am not fully over my ex.

My ex and I recently started talking about working things out and if it was possible. We both agreed that it is, but I would (obviously) need to drop my current boyfriend.

I don't have the heart to break up with him especially since my ex and i arent positive we can work things out.

I know i should end it with my current boyfriend anyway if I feel like something is missing, but i do love him.

Not like I loved my ex though, who I still love more than anything.

Any advice?