My boyfriend's ex-girlfriend often sends him messages. What should I do?

There is no way, but you can leave yourself a way out. Maybe they'll get back together and break up. In short, there are many possibilities. In today's society, no matter whether it is legal or reasonable, you can't stop them from interacting. What should I do if I think there is something wrong with my boyfriend and get married with him? You still can't. You might as well pay attention to a better man yourself. That's what society is like.