Why does this always happen to me?

This is the second time where an ex of mine moves on so quick and ends up getting the next girl pregnant. I'm talking she's pregnant in 2 months after we break up.. should I be sad? I really am sad and can't help but think what he saw in her that he didn't see in me.. I wanted kids , he knew that, but he gave one to her.
Why does this always happen to me?
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