I agree, but I would not look for a "perfect replacement" for a few reasons: You don't really want someone perfect and the next person shouldn't be a replacement, they should be themselves.

Have you tried talk therapy?

Sanada and unhappyguy are right though--perhaps just joining a club, or a social thing, or even looking around at those who are near you already--you can find someone who can help you get your mind off of her.

I feel (and of course, I could definitely be wrong) that part of this is because you feel you need her to be there to complete you--but in reality, you make yourself strong by what you do, not what someone else does.

Best,