There are a few things you can do to find your husband’s iPhone if he has not already told you. The first step is to check his phone’s location history. If he has been using his iPhone for a while and hasn’t used it in a while, you can check his location history by going to Settings -> Privacy -> Location Services and checking the box that says “Show location history when this phone is locked.” If he has not checked this box, then his iPhone may have been lost or stolen and he will need to replace it. The second step is to try calling him from his phone. If he has not used the phone for a while, or if the call goes through but he does not answer, then it may be that the phone is turned off or there is something wrong with it. If the call goes through but he does not answer, then you can try calling him again later from another number or even from his computer if he has an internet connection. The third step is to try visiting his house or workplace and seeing if anyone knows where his iPhone might be.