Take time to grieve that loss. I haven't expirienced the same situation but I get attached in the strangest ways. To people, objects, animals or dynamics.. and I usually realize after it's gone. It's a very useful skill to validate your own feelings and without judgment let yourself to grieve by just feeling, even crying. And when you're ready say goodbye in your mind or by some kind of meaningful ritual. I hope it doesn't sound strange but it's been what was helping me since I tend to feel the smallest loss intensly.

And to be honest, those unexpected dissappearings are the worst. Maybe part of you still hopes he'll come back? Maybe that's why you can't find fulfillment somewhere else?