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There is something else happening that you have not discussed. When the anger comes out "sideways" like this, it is almost always a sign of an unresolved underlying issue. Is it possible that he has developed feelings for someone else, wants to break up, but feels guilty about doing so?
You had a right to be mad with him for not telling you that he got a different ride home. Getting a ride home with a female coworker instead of you is already a concern, but then to get defensive because you were upset that he didn't notify you of the change in plans raises even more red flags.
But, I also don't think you are quite telling the whole story. If while you were mad, you accused him of having nefarious intentions with that female coworker then it makes sense for him to get defensive. You basically just said that you don't trust him which could have hurt him a lot, especially if those kind of thoughts had never crossed his mind.
It honestly sounds like you guys have a communication problem in your relationship. He failed to notify you of the change of plans and you failed to maintain a calm demeanor when you tried to tell him how that made you feel. Then you two when for 2 whole days without talking to each other, making the communication problem worse.
If you want to resolve this then you two need to work on your communication skills. Be open with each other, communicate often and in a calm, respectful tone.