So, everyone has to play to lose and who loses first wins? If I leave my king open to checkmate, the best move from AI would be to take that.. but the opponent

So, everyone has to play to lose and who loses first wins? If I leave my king open to checkmate, the best move from AI would be to take that.. but the opponent cannot do that. So, I get to leave my key pieces open and the opponent tries to do the same??