我没他那么爱吃辣，他没我这么爱吃甜。（没/没有, 爱/喜欢） "我跟他不一样..." doesn't work for verbs. “我跟他不一样高”（We're not of the same height.） is okay, but then we would just say which one is taller in most cases. so uh... use 我跟他一样 for the POSITIVE. => 我跟他一样喜欢吃辣的！ and save 我没有他那么... for the contrast. a little bit off topic: is the confusion caused by the translation "as much as.../ not as much as..."? if so, it would be easy. for chinese people, the first english word that would come to mind for 不一样 is "different", and for 一样 it is "the same".

我觉得可以说：“我没有他那么爱吃辣的，他也没有我那么爱吃甜的”

一般，我会这么说："我喜欢吃甜的，他喜欢吃辣的。" or "我口味偏甜，他口味偏辣。^_^

I'd say 我没有他喜欢吃辣的（食物），而他没有我喜欢吃甜的（食物）. You'd be safer to wait for a native speaker to answer your question though.