I totally understand where you are coming from with the miscarriages. when we really stopped trying it was a relief to know I did not have to go through that heartbreak again. The problem you have is that the only way to know whether you have a good egg in there is to keep on trying. I really think it is worth it for you as you do have a relatively good success rate with getting pregnant from transfers. There may be just one good one in there and you just have to find it.
I had a miscarriage at 38, our healthy DD at 40, and then 2 miscarriages after that (one being a very early loss of a natural pregnancy and then a miscarriage of an IVF baby at 10 weeks). Maybe we were lucky with DD and she was the only good egg in there but then again maybe if I had started IVF at 42 instead of 44, we would have hit another good egg. We will never know and you will never really know unless you keep trying I guess.
sorry, not much help but I totally get where you are coming from.