Go with the specialist. He/she is most familiar with CANCER and should be more experienced in the treatment of cancer. Your OB/GYN seems to be offended that you sought a 2nd opinion, and if so you don't want him as a doctor anyway. As far as your oncologist doing your "followup" , thats what you want anyway. You want a Gynocological Oncologist! Your surgery and treatment must be done by the specialist, and your followup care after the cancer is gone should still be done by the gynecological oncologist. She should be your primary care doctor from now on.
Good luck and God Bless
A Father who misses his daughter