Your post was truly touching. I had a lump in my throat just reading it.
So much of it I believe also.
We went down the path of telling absolutely everyone - friends and family - about what was going on. It was the verbal equivalent of the 'rip the bandaid off and let the wound air'. At the time DH and I agreed that the rule would be that there would be no secrets whatsoever, everyone would have the same information at the same time.
My DH's family sounds very similar to your DHs - step mothers, stepfathers, halfbrothers and halfsisters as well as brothers, sisters and mother and father. I have 3 brothers and a sister with various in-laws. Everyone was told. We've had issues before, particularly with DHs family, about secrets, so I wanted everyone equal. This was when we were still looking at an unknown donor whose information would be released when the child reached 18.
DH's family, in the main, baulked and ran away. To this day some of them still do not talk to us about the issue. (To be fair a lot of other issues have happened too). Those that didn't run away, or deliberately misunderstand, were quite happy to tell us that it was in the baby's best interest that they didn't know they were concieved through DI and we should keep quiet about it.
They told us about another family they knew of that had done this. Then I pointed out the irony that the secret was already out as they knew. They didn't mention the topic again...
Even in my own family people pushed their own agendas and recommended adoption rather than going through DI.
However, I'm very glad we did tell. There are no accidental secrets to be let out. Everyone knows where we stand. Everyone can go and cope with their own baggage. DH and I are standing firm.
The other thing it did was sort out the deep and meaningful relationships from those that washed up like driftwood on shore. DH and I learned that we have some wonderful friends and family members. It's a small group, but an intense one.
And if I hadn't have been so open, then one of our true friends wouldn't have had the knowledge or courage to come forward and offer, just when we needed him.
However, now we are not so open. I have told those who are still interested we have switched from unknown to known. A few of my friends and a few of DH's know who the known donor is. However we have not told either family. This is mainly because our donor is gay, and quite a number of our strongly Catholic family (both sides) have issues with this. Our friends don't have the same issues (we got to pick them!!)
However DH's and my family will have to deal with it at some point, because if this works our SD will be around for a long time to come. We thought we would break it to them when I am 3 -4 months pregnant and over the danger period of the pregnancy. But this will be in consultation with my DH and our SD. I'm not ever going to make them feel uncomfortable. Both families know that we changed our spiritual beliefs a long time ago - in my case, mainly because I met my SD and couldn't consolidate the church rules and his loyalty as a friend.
Oh well, I was never destined to make my family - both my own and DHs - feel comfortable!! Luckily my family still love me. I think DHs just can't work me out! DH takes the view that we are our own family. I love that about him too.
Anyway I better stop rambling as it's 11.40pm and I have a conference to attend tomorrow!!