You’re forgetting the (very likely) possibility of hitting diminishing returns at some point. If you want to maximize the amount of romantic love and there are diminishing returns, then it pays off to diversify at some point. Polyamorous people have also reported experiences where having a second relationship actually strengthens their first relationship, even if the three were not all in love.
Furthermore, you are presuming that people can just choose to spend all their time with a single partner, and any time spent with a second partner is gone from the first one. This is not so. For instance, suppose that A lives in San Fransisco where B also lives, but because of their job, A has to take the occasional extended trips to Moscow where C lives. That means A and C can see each other on occasions when it simply wouldn’t have been possible for A and B to see.
Or suppose that person A prefers spending nearly all of their free time in the company of other people, while their partner B prefers to spend half of their free time doing things on their own or with other people. In that case, A also dating person C who has the similar preferences as B will maximize everyone’s enjoyment and romance.
I would be very suspicious of claims that, in general, the strength of a romance would be a monotonically increasing function of time spent together. Most couples do not want to spend all their timed glued to each other, at least not after the initial NRE has worn off.
You’re forgetting the (very likely) possibility of hitting diminishing returns at some point. If you want to maximize the amount of romantic love and there are diminishing returns, then it pays off to diversify at some point. Polyamorous people have also reported experiences where having a second relationship actually strengthens their first relationship, even if the three were not all in love.
Furthermore, you are presuming that people can just choose to spend all their time with a single partner, and any time spent with a second partner is gone from the first one. This is not so. For instance, suppose that A lives in San Fransisco where B also lives, but because of their job, A has to take the occasional extended trips to Moscow where C lives. That means A and C can see each other on occasions when it simply wouldn’t have been possible for A and B to see.
Or suppose that person A prefers spending nearly all of their free time in the company of other people, while their partner B prefers to spend half of their free time doing things on their own or with other people. In that case, A also dating person C who has the similar preferences as B will maximize everyone’s enjoyment and romance.
I would be very suspicious of claims that, in general, the strength of a romance would be a monotonically increasing function of time spent together. Most couples do not want to spend all their timed glued to each other, at least not after the initial NRE has worn off.