Complex sentence: G.O.B. likewise is excited for the Bluth celebration, as he believes his co-workers are going to roast him, only he has been alienating the employees by boasting about his expensive suits.
Split into simpler sentences: G.O.B. likewise is excited for the Bluth celebration, as he believes his coworkers are going to roast him. Only, G.O.B. has been alienating the employees by boasting about his expensive suits.