Let me preface this by saying, I've read this thread for a long time but have never been active, so I apologise upfront for chiming in.
Like lily said, you and DH have clearly been through the gauntlet, and if I were you, I'd seriously consider finding a new FS who can give you more support and answers on the cause of the m/c's. From your history, I am shocked they've never encouraged you to do PGS / PGD. The technology has come a long way to where when they test on a d5 blast, they can take cells off (what will be) the placenta, and leave the embryo cells undisturbed. (Whereas testing on a 3d blast they have no idea what cells they are grabbing).
It seems the next logical step before going the donor route...
Again, sorry if this is out of line. xx