General statement:
* On aime deux. (This is the most straightforward translation, but it doesn't convey much emotion.)
Emphasis on the number "two":
* On aime deux choses. (We love two things.)
* On aime deux personnes. (We love two people.)
* On aime deux couleurs. (We love two colors.)
Emphasis on the feeling of love:
* On est amoureux de deux choses/personnes/couleurs. (We are in love with two things/people/colors.)
Emphasis on shared love:
* On s'aime tous les deux. (We both love each other.)
* On est amoureux l'un de l'autre. (We are in love with each other.)
More poetic:
* Notre amour est double. (Our love is twofold.)
Choose the best option based on your intended meaning and context.