Great relationship and plans to get married,, she has started talking and texting an ex....

We have a wonderful relationship and are perfect for each other, so recently and on accident saw she had been texting an ex boyfriend. and he sends her "good morning", "how are you doing", "hows your day" texts all the time. Now I completely trust her I really do, my problem is with the guy thats texting her. He knows she is in a relationship and has ZERO business texting her asking her anything in my opinion, as he has ask her out before. I look at this as a direct disrepect thing towards me. Should I say something to her? Or should I just ignore it? or should I go straight to him? .. I have been burned before and this relationship is my life and kids are involved and I just dont want some asshole guy trying to mess with that.. I nedd some advice