How do I do this?

I miss my ex. I straight up do. There was a good reason we broke up but it seems as if there's always something there between us. Which makes it really hard for me to give 100% to a future relationship in the making. So when my ex and I start talking again, it's like no one else is there. How do I navigate this? I know God has a plan for each of us and I just wish I had a sign saying, go this way. Or go that way. But there's this future relationship for me developing. It's amazing and "perfect" and I can't figure out why I keep looking back when I have my future right in front of me. Any words of advice would be amazing, or anyone's past experiences being shared would be very helpful, too. Thanks so much! Gods blessings be with you and your families 🙏🏼