This is really great advice it sure will work on the kids and I will introduce it and see if I can get my husband to agree to try it, I bet it will seem strange at first but then become natural, thank you!I have a suggestion which might help you, but it means that both you and your husband (and maybe child) need to alter your conversations a bit. I am a volunteer at an international organization, and we use so-called "finger rules" to keep conversations flowing without interruptions in large meetings.
During discussions, interruptions are strictly forbidden. However, if you have something to say, you hold up a finger/fingers to indicate that you have something to say, and at an appropriate point, you are given your turn. I have the same problem as your husband, but I never find myself interrupting while using finger rules as long as everyone follows them. I don't think you need to use most of them as they aren't all relevant in a conversation between two people, but I think 2-3 would be helpful.
i or holding an index finger up indicates that you have a new topic of conversation. This means that you can keep the conversation going for now, but the person has something new, unrelated to say later.
ii or holding up the index and middle finger says that you have something to say relevant to the current topic. This always takes precedent over one finger, but you still need to allow the person talking to finish their thought.
bs/joke or holding up your thumb and index finger together forming a circle, like you are complimenting the cook at a French restaurant means that you have something to say which only makes sense now, and if too much time passes the moment is lost (frequently jokes). This takes precedence over all else. If someone makes this sign, you should finish your sentence and then stay silent, let the other person make the comment/joke and then continue your point.
I know this is not a typical way to communicate, but I find it really helpful for me, and wish those rules were followed in daily conversations as that would make things much easier for me. I tended to use them in smaller meetings than they were normally used in when facilitating as it made things much easier for me (at least if people were paying attention). Losing your chance to say something can be very aggravating for someone on the spectrum, so this is a polite way to make sure everyone has their say. I recommend at least trying this.