I do understand where your current boyfriend is coming from.. Afterall, you were with your ex for SEVEN years.. You guys have obviously shared a lot throughout that time..And now here comes your current boyfriend ( who I'm assuming you havent been with all that long) and he prob feels he has 7 years of some great times to compete with..But on top of that, your ex is sleeping over and maybe feels since you guys ARE in fact leaving off on good terms, maybe there is a chance he might need to come back for something else he "forgot" therefore having the same sitaution again. All you can do now is prove how much you care about him & would never do that..Explain to him how you and your ex are completely over and he's just part of your past now. I agree calling him is completely childish, you shouldn't have to go to that extreme to prove yourself to him. Just give him time and I'm sure he'll get over it. Just for now, try to lay off talking to the ex for a while, at least until he feels a little bit more comfortable and this all blows over