Hey, I can imagine this might bother you. And you are definitely not wrong for feeling disrespected, because what you feel can never be wrong it is what you are feeling after all. And whether or not you should be worried is something nobody here can answer, but you and your husband. There are plenty people whom are still in touch with their exes in a friendly way (and nothing more). I dont know what kind of relationship your husband has with his ex, but maybe you could ask him this. One of the most important parts of a relationship are communication and trust. Sit down with your husband and let him know how it makes you feel and why. I dont know if this helped a bit :o
