At some point do people become immune to break-ups or getting rejected?

If a boyfriend wants to break up or I get rejected (''oh we don't have chemistry, oh it's not you the problem BS, etc) this is my reaction now:

''Cool, bye, next''.

I find myself going to the movies with my friends and smiling on pictures. My stance now is whoever wants to stay in life permanently great and whoever wants to leave, great. I'm officially immune to break-ups or rejection. Is this what happens to some people too?

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If a break-up happens and I were to be invited to a party the next day, I find myself going to the party and not be affected one bit by the break-up. I got immune to it.
At some point do people become immune to break-ups or getting rejected?
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