I can relate. My Fiance and I have been together for almost five years, we are getting married next year and a year or so after that we would love to start our own family. I wanted to lose weight to be healthier all round but, trying to conceive was a big part of the overall reason. I want to incubate my child in a healthy body and give he/she the best start possible and I plan to continue eating well and still work out and do prenatal yoga (obviously not to loose weight), that whole 'eating for two" thing is a load of bologna and I think too many people use it as an excuse to pig out, I've seen this with my own eyes. Sure you have cravings but, just like in weight loss you have to learn to not always give in to those food cravings. I've seen friends who are quite overweight experience problems during pregnancy such as preeclampsia and hypertension- I don't want to risk the health of our future child(ren) and also my own health. I think it's fantastic that you are getting in shape to become a mother, good for you- very admirable!
Here is a great link with lot's of info in regards to overweight women and pregnancy:
http://ezinearticles.com/?If-You-are...nant&id=176934