I never had to explain dating to my alters. my alters took control based on dissociation.... when ever something happened in my life to cause me to dissociate then the alter who's sense of agency it was to handle that situation would take control.

you seem to know and can communicate with your alters. maybe you can ask them why they are uncomfortable with you dating. that will give you a way of talking to them.

let me give you an example... i have a very sensitive daughter. she has many mental and physical health issues. sometimes when my wife and I want to go out she gets upset. we have to take extra time with her by sitting her down and saying mama Sandy and I are going out to dinner later on tonight. any questions? then she asks her questions and we answer hers keeping it very simple and to the point. yes we will be calling to check on you all, yes we will be taking a taxi home, no you can not come. this is just for grown ups.no you can not stay up past your bedtime. yes we can see if that friend can come over for the night. yes we will wake you up to tuck you in. ....we usually go through about 20 or 30 questions until she gets to the point where she says ok can I help you make dinner, or can you color with me before you go.

my suggestion is do something similar with your alters find time to sit down and let them know you are going on a date and ask inside if there are any questions then answer their questions in what ever ways you feel fits how and why they want that information.

other wise there is no right or wrong way to explain dating to littles be it biological or insiders.