I know where you are coming from - shortly after BD, I received news that my parent was terminally ill and at the same time, I had some worrying medical "inconclusive" results. I never shared that information with anyone because I just felt less important at that time. Waiting for those results was almost as bad as the patience needed for DBing.
I will tell you what I learned - and it was an amazing lesson. There is never NO ONE and there is never a Plan B that allows you to sacrifice your own health. I was able to take this in my own stride because there were no kids involved. You do not have that option. I absolutely get how emotional this is for you. Try, for a moment to put the emotions away.
What do you need to do? And please, these are only my suggestions given with much compassion in the hope that they will help.
Perhaps your conversation with your H should happen before you get the results. Maybe feel out where he is at and give him a chance to "get his toe wet" rather than have the sky fall on him. MLCers do not react to "bombs" well. If your tests come back good (I am sooo routing for you) - great! Then you can tell him that. Prepare him for the day you will know.
You did not say (or I do not remember) how old or how many kids you have. If they are old enough (teenagers?) then perhaps leaning on their friends parents for rides to school, etc. temporarily may be an option. Time with their friends will distract them from worrying about you and let you concentrate on you. I also recall you saying on your previous thread that H's family seemed to be on your side. Don't worry about him - pick someone to be the back up. In fact, why not discuss it with him as a way of taking off the pressure, so you both have the same Plan B? In fact, if you choose someone to help and approach that person together, it may smooth out the edges a bit. He has been contacting you and acting like a friend - continue in that vein.
His family know you are going through a tough time. And this is NOT about picking sides or your R. This is about helping family who needs it. I know how hard it is to ask for help, but sometimes it is the strongest thing that you can do. I was so surprised when strangers were the ones I could rely on - and also surprised at how many people had already been through what I had and were willing to help.
Reach out, BRNR. And do not worry about getting too emotional, there is no one on earth that would fault you for that.
Keep us posted. We are here to cheer you on! Wishing and praying for good outcomes!