What do boys/girls flurt with others while in an agreed upon relationship for?

Question

could the problem pinpoint at the idea that the other just aint good enough fit?

Answer 1

are you a lawyer or something  ?

"agreed upon relationship"  ?

No one talks like that.

Answer 2

its fun

Answer 3

uncertainty, sometimes selfishness, insecurity & most of all fear that what they have may not work

Answer 4

From a biological  evolutionary standpoint there are several good reasons.

1) To keep your options open in case your relationship ends.

2) To keep in practice in case your relationship ends.

3) To remind your mate that they better treat you well because you have other options.

4) To prove to your mate that other people find you attractive so they made the right decision in choosing you.

5) To set up opportunities to cheat.

Jealousy is generally an effective way to get someone to take you seriously and not for granted.