4 miscarriages .... how many more :'(

Chelsey
Hi all I have had 4 miscarriages the first two were a year apart, I generally loose my pregnancy around 4 months. My first two were with a different daddy than the last two. The 3rd pregnancy two years between the last miscarriage again lost it at 4th month mark so with the okay from the doctor tried a fourth time. The fourth one i lost at a little over two months. I have had numerous amounts of testing an six different doctors cant find anything wrong with me or my partner. I just want to know how many more times i will go through this or if anyone has any ideas of why?