Most Helpful Girl
Is it possible that there was more to the story of what went on that night? Perhaps something he said or did that night scared her.
Otherwise, no, it wasn't right of her to leave for three days. Unless she was genuinely scared for her safety, she should have tried to work things out when the issue was still fresh.
Most Helpful Guy
It is okay to leave if you need a little time to get your temper under control. Staying gone overnight is not okay unless she tells him where she is, explains why she is gone, and he either trusts her or has some way of verifying that what she is saying is true. Otherwise, she is giving him reasons to suspect that she is not being faithful to him.
It sounds as if they both owe each other an apology but, more importantly, they both need to renew their commitment to making their marriage work instead of simply walking away when things are difficult.