Marble cake with Chocolate Chips

My kids love chocolate so i made this marble cake with added cocoa and chocolate chips. I had made this cake a few times and it always turn out good. but today, the cake doesnt seem to be good, its dry and the marble effect is not that attractive. The reason could be i have added the eggs too fast and the mixture become curdled. That is why the cake texture turn out dry and not Q.

Marble Cake @ Sugabakes

Marble Cake @ Sugabakes

Marble Cake @ Sugabakes