jealousy is a feeling that is difficult to bear

It is hard to control feelings, but you can, to some extent, control behaviors - if he comes back and/or in your future relationships, can you abstain from checking the guy's phone log? Can you abstain from asking questions about who calls your boyfriend? Is it possible for you to keep boundaries? Can you journal/post about jealousy somewhere not visible to bf, when you get the feelings, instead of acting out by violating his privacy (and, in this particular case, the bf's employment agreement by which he surely is supposed to keep his work email private)?

Also, how would you feel with tables turned? Would you enjoy having a relationship with a guy who needs to know everything about your conversations with other people?