The time to talk about this is when it is not happening. When people are so upset they can’t even hear each other, there is no point in trying to talk about a problem. As you have already discovered, screaming over him doesn’t help. Being silent doesn’t help either. Being silent makes you feel diminished.
Conflict is inevitable in any relationship that is worth our time. People are individuals, even when they are much alike in temperament and interests. When people first become romantically interested in each other, all they can see, usually, is how alike they are. As the relationship develops, differences emerge. When those differences don’t threaten each other’s beliefs or value system, they are often seen as interesting and enriching.
But when there is something about the difference that challenges someone’s dearly held beliefs or that call into question someone’s values or something that they have some shame about, the hard work begins. In order to continue building the relationship, those differences must be addressed and worked through. Either the couple comes to some new agreement about the issue or they find a way to respectfully agree to disagree. Appreciating each other’s positions and feelings, even when we don’t agree, is part of what deepens and supports a long term relationship.
I can’t answer your question about whether your friend is being abusive. Emotional abuse is characterized by verbal aggression that includes name calling, humiliating or intimidating the other and manipulation. It occurs over time and erodes the victims sense of self-worth.
Two incidents in 6 months, suggests that he was more frightened than abusive. People who are frightened or hurt often behave in ways that are difficult to take. It may be that the only way he knows to handle conflict is to shut it down by silencing you. If that is the case, talking disagreements through during a calm time so that both of you feel safe may be an important step in deepening your relationship.
On the other hand, if the only reason it hasn’t happened more often is that you are walking on eggshells all the time, your relationship is in trouble. No one in a love relationship should have to be constantly on guard so they don’t activate the “monster”. No one should feel silenced. Accommodating to it will only drive you to be more and more silent.
I don’t have enough information to make a judgment about what is going on in your relationship. I hope this information helps you figure it out.
I wish you well.