As someone who broke (along with many others) an engagement, it is far better to break when one sees red flags than to proceed with what will be a rocky marriage that will end up in divorce. Shalom bayit is one of the most important things. In many cases, a person will act differently post-engagement, so it is always best to re-evaluate when one sees the warning signs. In my case, my ex-kalla had anger management issues. She would throw a tirade and take off her engagement ring. She even did this on Yom tov.