Patellar dislocation?

When I was pregnant with my first daughter I tore a ligament in my knee. I was told it is because relaxin is released during pregnancy and that relaxed my ligaments and caused the tear-also my knee track out my doctor said. I haven't had any problems for two years and I even had another pregnancy with no problems. Then in the past couple of weeks my kneecap slid out twice while I was doing routine things. I did start taking yaz and if yaz makes my body think it's pregnant could it be contributing to my problems? The doctor told me it could continue to happen and he is pushing for surgery but i couldn't afford to miss that much work or school for at least another year. I try to keep a tru-pull brace on it to help and it does but because it's applying so much pressure it leaves burning red marks by the time I pull it off and I can only wear it about six hours at a time. Please answer all the questions in here that you can. Thank you for any advice.