What is the point of dating or relationships when you already know how it's gonna end

Obviously, we all know we will end up dead so what's the point of living, but what I mean is being in a relationship, after a few dates, when things get normal and become your routine, you already know and expect what's gonna happen, the romance, the first year or so of the relationship, the first fights, the disrespect which comes slowly, the cheating, the break up, the ruining of your life when happens and the depression and the suicide thoughts, what is the point of it all, are we dumb like lab rats?