It is not ok for him to break your phones, throw things, etc. I would not stay with someone who did that.

It is also not ok for you to have an emotional affair (Google it and do some reading) and to refuse to end it (the only respectful thing to do is to cut off contact with Q). While I wouldn’t stay with a person who demanded that I cut off contact with someone who is only a friend, and where there are appropriate boundaries on both sides, he is in the right to insist that you cut off contact with Q. That emotional energy that you are putting into Q should be going into your relationship; if you don’t want to do that, you should face up to that fact and break it off with your boyfriend.

Edit to add: Any couples therapist you go to will tell you that you need to cut off contact with Q, so I would be prepared for this if you decide to do counseling with your partner.