"You make me happy, my love."
The word lover is not used exclusively to mean a sexual partner, although it is often used to mean that. This sentence could be translated with lover, but the translator runs the risk of the audience assuming a sexual partner is meant, which the Klingon word does not imply or prohibit.
The word parmaqqay is probably closer to meaning a sexual partner, but even there we're only told so in Star Trek's safe-for-television kind of winking acknowledgement. I suspect without evidence that parmaqqay implies that the partners are bound to each other in some way — friends with benefits could not be called parmaqqaypu'.