Make him regret losing you?

How can I make my boyfriend regret losing me and make him thrive to get back to me so I can still tell him no , even if he is this type of person who has high degnity and would hardly show he is missing me?
The thing is we have been together and it was a real strong love and I always were able to turn him on, he always knew and has been telling me that ut's definitely hard to find someone like me and it would be almost impossible to find a girl that would do all that happened for him despite lots of downsides he got , and after all that I figured out he can't stop texting back and forth with a girl he has known since a long time and seriously cuz of this I told hime it's over although we were supposed to get married!!
How can I make him really really regret me for the rest of his life?
Please guys what are the creative ideas , and what is something that you have tried and worked really well?
Goes for both guys and girls 🤗🤗
Make him regret losing you?
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