My boyfriend has a 92 civic DX sedan 5 speed. We would like to know how hard is it or is it hard to put a 91 accord ex engine into it. The reason we are asking is because he already have a 91 accord engine and the engine in the civic is bad.

its a pain in the butt and not really worth it

Yup, go look at the H22 swap guide, it's going to be pretty much identical.