is incest really happen?

[RajV]

but not all cousin are in incest family tree.
in my case I will marry with my aunt's daughter(mother's -sister's -daughter) so in that case she is my cousin but not incest.

incest cousin is when have sex with your father's- brother's- daughter that is called incest.

Agree Actual Incest is Mom or dad and real siblings,rest is defined in various ways by communities across the world,however its the most common dream ,i have myself done with cousin and lusted for ma.