I am not an expert, but like you I am totally bilingual, very comfortable with both English and my mother tongue. I learned English when we moved to the UK when I was about 9 years old. I know how easy it is for a child to learn 2, 3, 4 other languages with ease under say the age of 12. Beyond that most find it difficult to speak a 2nd language as a native, without an accent.
What I have seen is that many children in the UK lose their mother tongue because they do not have consistent and regular exposure to it in the home.
I would say each of you should speak to the child in the langauge that you are most comfortable with. I guess in your situation, as your husband is not a native speaker of French, it might be best if you stick to French and he to English. Like you say, the resaon you speak French so well is because your parents only spoke to you in French and presumabley you learned English at school and in the community ?
I think what your parents did was perfect and very sensible. Where it all goes pear-shaped (I have seen it often with parents who speak my language and who live in london) is where the parents start speaking to the child in different languages, very inconsistently, half day in English, half day in Swedish, the next day in Spanish, etc. This just doesn't work in my view. Whatever language you chose to speak to the child, stick to it !
My son (now 2.2 years) has never ever heard me speak to him in English and never will. The minute I start speaking to him in English, he will think it is ok to reply to me in English and then that will be it. That is where it all went wrong for my sister. She has 3 children all born in the UK, not one of them speaks our language because she gave in and started to speak to them in English the minute they went to school.
I also often hear parents or grandparents who speak English as a second language speak to their child in English with a heavy foreign accent and usually bad grammar, and I think why in god's name do they do it ? It is much better and easier to speak to a child in the language that you are most fluent in instead of a language you speak poorly !
Best of luck !