Hmmm thats a bit difficult if he isn't going to support the idea but I think as another poster said he is giving you an out and also he is scared for you.
We have to remember that although we HAVE the band our partners LIVE with the band and so they need to be up to speed on all the info that we have. It can be daunting for them. I was lucky, my husband supported me the entire way and is thrilled that now he knows he will have me around longer!!!!
BUT if you feel that you want to try "one last diet" or if you have issues about surgery or foreign devices etc YOU have to work this out BEFORE you have it done. There is absolutely no point in putting yourself through this if you have too many concerns because you will end up sabotaging yourself and cheating your band (yes you can cheat, you just have to not want to)
I could try to convince you by saying I eat out all the time and have no problems with it, or by saying it was the best thing I ever did for myself, but that isn't what it's about. Its about you (and I mean that collectively as I believe his support is very important) KNOWING that this is what you want to do at this stage! It might well be the very best thing that I did for me, but we are all different and you have to know it it what you want for you.
Good luck with it and I wish you every success in whatever decision you make.