Can someone give me some advice to put him in his place without loosing him forever?

Me and my boyfriend had been together for almost 4 years on and off, he was a really bad temper and tends to be very moody so sometimes he explodes and it causes a sudden break up. We had been really great together until I heard from someone recently that he was fooling around with another girl and so I confronted him about it. He freaked out and broke it off saying he thinks we should see other people. I'm so confused right now and deep down I feel like this is just the wrong choice for both of us. Can someone give me some advice to put him in his place without loosing him forever?
Can someone give me some advice to put him in his place without loosing him forever?
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