Reha,
Since you're really conscious about staying fit after marriage, I think you'll make more effort to maintain yourself. I have married friends who are very conscious about their weight/figures, and because of this they continued their efforts of staying in shape even after marriage. And they look great! Some of them even have kids and they look the same as they did before they got married.
Just establish a work out routine. You lose weight fastest when you combine cardio with weights. Set aside a few days a week when you will exercise. You can go to they gym or exercise at home. Or you can go running outside in your neighborhood 3-4 times a week like me and do arm weights/crunches at home. That's what I do and it helps.....although I've just gotten back into the routine.
When you go out, eat healthy. Choose items from the menu that are low cal. For example, opt for water over sodas. And choose salad over fries. Or soups over fried goodies. Just because your hubby is sitting across from you at a restaurant and eating.....doesn't mean that you shouldn't eat at all. You should eat....just eat healthier. Talk to your hubby and limit the frequency that you both will be eating out. This reduces spending and calories. Keep yourself well hydrated. Filling up on water can prevent you from overeating.
And stock your pantry with healthier snacks. Often times when one partner eats healthy and works out.......the other partner gets motivated so it becomes like a lifestyle. You have an understanding fiance....and while he accepts you no matter how you look......I'm sure he'll understand that you're just trying to stay fit and healthy.....and he can even help support you when he understands how important this is to you:)