So sorry to hear about your losses.

You're in good company, though.
I have heterozygous MTHFR, also slightly elevated IgG. My miscarriages (there were 4) were all early 1st trimester, after a heartbeat was found. My reproductive immunologist was a leading researcher (there aren't a lot of RIs around though so that's not saying much I guess), and in addition to the typical baby aspirin/extra folic acid/lovenox/dexamethasone/ivig therapies that most doctors recommend for people TTC with MTHFR, he convinced me to try something called lymphocyte immune therapy or LIT. It's not yet FDA approved, but most other countries are doing it with great results, so I went to the nearest one to have it done (Mexico). I have no idea how effective or not effective it was, but it was only $400 (which is cheap compared to all the other TTC expenses we were considering), so I went ahead. It's just a blood draw for your husband and a shot in the arm for you. No big deal at all. And, my next pregnancy was a great big success.
However, the lovenox made me bleed heavily in my first trimester, so I had to stop taking it. It was recommended that I do IVIg, but I didn't. It was expensive, and my clotting factors were borderline. Had they been higher, I would have gone ahead with it. So all I took for MTHFR was the LIT, baby aspirin, folic acid, dex. And prenatals.
So I can't be certain that the LIT worked, but... I got pregnant AGAIN, and I was off all that other stuff. Even the baby aspirin and supplements. I was breastfeeding, only had one cycle, and boom! Got pregnant, stayed pregnant. How unlikely is that?? I wasn't even trying. Since all the other meds were out of the picture, only LIT was left. It's permanent (supposed to treat any possible immune response your body might have against your fetus which has your husband's white cells).
Good luck in your future pregnancies, and many hugs!