a big NO-NO.
Incest, think of that.
You can always ask your parents for a little advise honey. I think you were confused on some things about love and relationship.
Always check on the 10 commandments before doing anything.
If you love in normal way your relatives it isn't bad,but if you love a cousin and you desire him to be your partner,it's a big problem!Because if you would ever want to marry him,you couldn't make children!