We have been dating for 6 months. He was really sprung at the beginning and very affectionate. Now I feel like maybe his spark is gone for me. I am a very pretty girl, great figure and have my head on straight. However, he is a bit overweight, and gets insecure about his recent weight gain, and no longer touches me. I don't know what happened or what I can do. I put on sexy outfits for him, touch him all the time and tell him how I care for him the same and the weight gain means nothing to me. But now as a confident girl, I have become insecure, and I don't know what to do to entice him anymore or if... the flames just gone! Help!

I suggest you stop with the enticing and start talking. How else to get to what's up?

Communication is best. In most or all situations, in this situation express your worries. Just by communicating it might just patch it up, especially since you've been dating for 6 months.
Hope this helps! :)