Although your risk factors are very high, there are no guarantees that you will get melanoma again. My dad had and survived stage 4 melanoma back in the 1970's. While he regularly battles less serious skin cancers, the melanoma never returned.
My dermatologist gave me a brochure not too long ago, from a company that does medical photos for high risk patients so all of your moles can be watched more carefully. The drawback is that it was about $500 and is not covered by insurance.
One thing to keep in mind, while melanoma grows quickly, at least this is something that normally can be seen. I think that's a huge advantage over some other cancers that quietly grow on our insides and may not be caught early. I have a similar skin cancer history and skin type with the added genetic factor thrown in for good measure (lol). I'm doing everything possible to take care of my issue and when my time comes, I am determined that it's not going to be due to skin cancer.
You are doing all the right things. You do sound like you have a vigilant dermatologist although I understand your concern about your life being in their hands. They are pretty good at identifying troublesome moles. You can also educate yourself well about what to look for and then you will have two pairs of eyes checking.
Take care. As your melanomas were early you have an extremely good prognosis.