how do you deal with it?

So here's a bit of background, I am extremely happily married to the most amazing man ever. He's sweet and supportive and loving, we just bought our first home and have four (soon to be five) dogs and almost an acre in the country. We've been ttc for six months, and we had one mc before that (second trimester twins we lost that we didnt know we had due to my mirena) a chemical pregnancy in August and this month and a six week mc at the beginning of november. I feel like a failure, obviously we can get pregnant but I can't keep them and I don't know how to not just want to give up.... We recently found out it is mostly due to the fact that he's o positive and I'm o negative so my body pretty much keeps rejecting the pregnancies...I don't have any antigens and I've had the rhogam shot but I still can't stay pregnant... its devastating every time it happens, it's gotten to the point I want to pack up the nursery and forget about it all together..does any one else have this problem? I've tried just forgetting about it and "letting it happen" but it's gotten to the point where it's always on my mind, especially when I see my friends getting pregnant so easily. ...sorry about the long post I just don't know what else to do, any advice is appreciated thanks so much