you told him about the other guy because you thought he would be interested - the only thing he was interested in was you talking to another guy why when you two are seperted and trying to work this out and having problems with the pregnancy would he be interested in someone else's life?
The other thing you said was he yelled something about him (the person you were talking to) being better than himself can't remember exactly what you said - but to me it appeared that you may have been saying the other person is doing well in their life and he took it as you telling him that he wasn't
He tells you that you are absolutely wrong just say 'that saddens me that you think I am so wrong' and change the subject
he yells to get his point across - then you get quieter the louder he gets don't escalate with him and when you get quiet you really have to take control and say 'I hate yelling and arguing this way so I am going to go and will discuss it later with you when we both stop being angry and yelling' and then hang up
you are allowing him to yell by continuing to listen you allow him to argue by arguing back
change your behaviour you change his
when you talk again you can say it is healthy to get disagreements out in the open - but by discussing them not arguing about them loudly - so lets make a pact if we begin to argue and get loud then we won't talk till we have both calmed down and instead of arguing about who is right or wrong we will talk about the solutions to our disagreement
