GC holder marrying E2 holder

[ucfbritgirl]

I am a GC holder from the UK who is eligible for citizenship. I've recently become engaged to an E2 dependent (dependent on his father because he is s 20) visa holder also from the UK. Does anyone know where we stand legally on this after we get married? It's all very confusing and also frustrating because my fiance can't work at the moment. Should I apply for citizenship before we get married? What would his status be if he married me just as a GC holder?

Any help appreciated. Thanks.