This is interesting, but I'm dubious about the science behind it.
Rabies is a good example: it causes encephalitis (inflammation of the brain). Aggression is not the only symptom. It can also cause anxiety, confusion, paranoia, etc.
A virus that triggers a sexual response is a rather specific mechanism. In order to spread to epidemic levels, it would need to develop in a certain type of environment--probably one where sexual contact is often unprotected and nonconsensual. There are some developing areas in the world where this is (unfortunately) the case. But how would a disease like this spread into more technologically/medically-advanced societies, ones where law enforcement is also much stricter and more effective?
Also, sexual arousal is a very individual thing, and is not necessarily innately aggressive. In order to drive diseased people to rape others, the virus would have to also incite aggression. Rape is often, after all, less about sex than it is about power, dominance, and control.
Such a mechanism would also probably lead the infected to take advantage of weak/defenseless victims. This could get into a very dark and disturbing area involving abuse of children, the elderly, etc.
The story would have to be handled with extreme care, IMO.
Just some food for thought.