per+ fidy=without fidelity i.e cheat upon ur partner,,in general cheat or breach something
sounds like "dhokadhadi"
GF ke hotey hue bhi woh kisi aur ladki "Par + Fida" hoo gaya.. means he is breaching in that girls faith.
fidelity for par-purush
who cannot maintain fidelity (=faith) of one person.