Boyfriend faithfull or a little rat ?

been with my new fella since september last year and everything was going great , till my ex found out and didnt want him around ! told him to stay away and theatened him , etc. we carried on regardless of my ex anyway and few months down the line found out he had someone txtin him who he didnt even know and arranged to meet them and make a nite of it back at their place ! i found out because they txt me of what he was doing , and said be carefull he is a player ! i thought it was his ex but it was not ! he said he was single and would love to meet up with them , he tried to deny everthing , but i tld him i have the txts here , he tried to say it was me messing around aswell he said to this person that he would finish me for them ! thats what got me the most but also he actually went to meet them ,tried to deny that to until i said so you didnt tell them you were in the carpark and what car you are in no ? he replied yes i did sorry xx