Second Chances when you truly love ?

I love this guy so much we have been through so much , we have had our ups and downs and we would get mad argue and then have wonderful days like any other relationship, I would get mad and say things I didn’t mean and I understand I messed up there . I tried to calm it but when I get mad it just gets out of hand and well he met a girl , and they were talking as “friends” but sooner or later he broke up with be brought up some arguments in the past as an excuse and then dated her . I waited and waited , because he’s part of my life we dated for so long and he’s just everything to me it hurts me because I didn’t know he was capable of this , and well today him and that girl broke up . What if he comes back ? Can people really win you’re trust back ? And do people deserve second chances ?