Even if they all still gather together when it was holiday and played together from time to time, but it was no longer the same. The four of them no longer played together so much.
With Mark and Lucy being together, Anna didn't want to be the high wattage bulb between the two of them and being forced to eat dog food. Anna also has her own fiancé and spend more time with him.
Thus, her interaction with Dylan was decreasing.
They no longer as close as they used to be.
Even though Anna felt a bit uncomfortable, but she also understood that it was a normal thing to happen because they were all growing up. They were no longer children and there were differences between men and woman.
So Anna didn't force it.
The two of them shouldn't have much interaction anymore.
Until the broken engagement.