My two girlfriends Z and Y met through me, but zy became good friends and didn't even ask me out for dinner. I feel like an outsider.

Just tell them that you two met through me and that you are both my friends. As a result, you know me and don't want me. You left me alone and went out to play. You two are so close that I'm an outsider. You are so ungrateful. Your behavior has deeply hurt me! Come straight to the point, you didn't do anything wrong. What is wrong is that these two ungrateful and inhuman guys … why are you still sad here and vent your unhappiness directly on them! Comfort you, don't be sad, the baby is right, it's their fault, it's so unkind.