You can miss someone and still know walking away was right. Both feelings can share a room.

Wanting someone back is not evidence that leaving was wrong. The mind treats longing as a verdict when it is only a report on what you lost, and you can lose something real by walking away from a situation that was bad for you. Two true things side by side is the normal shape of this, not a contradiction to resolve.

Let the missing happen without putting it on trial. You do not owe yourself a running justification for a decision you already made carefully. If the ache turns into reconsideration, look at the reasons you had at the time rather than at how tonight feels.