Is it right or wrong for me to be angry when my boyfriend holds another girl's hand?

You're right. He has the cheek to tell you this happily, without considering your feelings at all. You are angry, but you can think about whether you are wrong or not when you are angry. You can do it. It is obvious that you love him very much, and even a tolerant woman can't tolerate her boyfriend like this. As a bystander, I don't think you should be advised to leave him. I think you are reluctant. Otherwise, you won't feel wrong ~ tell him well. Although you love him very much, you have to look at what he is thinking, speak out all your uncertain and doubtful questions and solve them. Many things must be solved through communication. If a woman doesn't get angry when she sees her boyfriend holding someone else's hand, I think that's not normal! Don't be too sad, maybe they really have nothing. What you have to do now is to choose a suitable time and sit down and have a good talk with him. No matter what the result is, I think it is much better than your present state. I wish you happiness ~