Why do I feels so guilty?

Well, My ex cheated on me but he said he would never do it again and he did so I told him its either her or me and he said me and I told him never to talk to me again and three days later I found out that he commited suicide...

Well just remember none of this is your fault! He cheated more than once and well he broke the promise, lied and broke the trust! That might not be the reason he committed suicide, theres probably lots of other things that led to that situation! You shouldn't feel guilty!