Ovarian cancer remains a rare illness regardless of the type of cyst. If your doctor thinks it is safe to wait and check again in two months, it probably is. At 5 cm it is at the size they start to think about removal (of the cyst) but many will want to wait and see if it is capable of just going away on its own first. If no improvement after 2 months, they will take the assumption the cyst is going to be stubborn and remain, so removal is the better treatment.
I am only 24 and I have a handicapped 2 yr old son. I have had several other health problems and have been debating if it is even a possibility for me to have more children. 2 of the cysts reptured on their own and the 3rd they didn't say if they did a biopsy but I am assuming it was benign. None were septated though. Do you know how often septated cyst become cancerous? I have been told it is more frequent than other cysts. I have also been checked in May and I don't have endo.
What did you learn about the previous cysts? I imagine the ones that were removed were tested and must have tested benign. So if they were benign, then what's to say the current one is not also benign? Septated cysts have inner walls/sections so by their nature look more concerning on an ultrasound. But an ultrasound cannot say whether there is cancer present. Were previous cysts also septated?
If the cyst problem persists and requires you to always have them checked and possibly removed, you never get any peace. If you really want the problem to end, then removal of the ovaries would solve things, IF they are truly ovarian cysts and not ones caused by endometriosis. If endo is the cause, then they would recommend a hysterectomy. All of these are really final decisions and not easy ones to make. If you are young, loss of ovaries can require you to take hormones until you reach an appropriate menopause age.
Birth control pills and pregnancy often get the ovaries working properly again since they both give them a rest with the hormonal changes they cause. You don't say how old you are or what your family plans are. All these factors weigh in the decision process. Your doctor should be discussing all these options with you.