Serial monogamy

Serial monogamy is like having a special toy that you really love and play with all the time, but then one day you get a new toy that you love even more. So you start playing with the new toy all the time and don't play with the old toy as much.

In relationships, people sometimes have a "special person" that they really like and spend a lot of time with, but eventually they might start to like someone else more and want to be with them instead. This means they end the first relationship and start a new one with the new person.

Just like how you can have lots of toys throughout your life that you love, some people have lots of different "special people" that they have relationships with over time. This is called serial monogamy. It's like having lots of different "special toys" that you really love one at a time.