Don't love two people at a time.
Dōjini ni nin o aisuru na.
coincident with; while; simultaneously
-ian (e.g. Italian); -ite (e.g. Tokyoite); indicates nationality, race, origin, etc.; -er (e.g. performer, etc.); person working with ...; indicates expertise (in a certain field); (usu. in compound words) man; person; people
indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.
love; affection; care; attachment; craving; desire
(sentence end, mainly masc.) indicates emotion or emphasis; (used with masu stem verb) command; (used with dictionary form verb) prohibition