Why are so many guys so insecure and jealous in relationships nowadays?

Yesterday i was at club with friends this couple talking with bartender i was there tbh girl was hot we had intense eye contacts many times her boyfriend went to washroom so i reach to her and we talk. We flirt. Exchange sm. Her boyfriend caught us talking dude immediately got angry took her n left immediately with anger stare to me 🤣🤣🤣🤣🤣 bro she will be in my arms in next weekend poor guy. 🤣🤣🤣
Why are so many guys so insecure and jealous in relationships nowadays?
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