“Why does it never feel finished with him?”
You already know the answer isn't “because of his Venus.” It's because the two of you keep meeting in the same unfinished room. Your Moon in Cancer wants the conversation that was interrupted — and his absence keeps it interrupted. That's the loop.
What your chart suggests isn't walking away or going back. It's noticing what your seventh house does every time you reach for the phone: you're not missing him, you're missing the moment you almost said the true thing. Say it somewhere. It doesn't have to be to him.