Formal:
* Je t'attends, mon amour. (This is the most literal translation and is appropriate for a more formal setting.)
* J'attends avec impatience ton retour, mon amour. (This adds a sense of anticipation and is slightly more affectionate.)
Informal and affectionate:
* J'attends mon cœur. (This is a very sweet and intimate way to say it.)
* Je t'attends avec impatience, mon chéri/ma chérie. (This is a more casual and affectionate way to say it.)
* J'ai hâte de te retrouver, mon amour. (This expresses your excitement to see them again.)
Romantic:
* J'attends ton retour avec une impatience folle, mon amour. (This is a very romantic and passionate way to say it.)
You can choose the phrase that best suits the situation and your relationship with the person you are addressing.