My ex-wife is married and my daughter is 14 living with me 50/50, should I still have to pay full child support. Divorced 8 years.

The 50/50 split does not mean there is no child support owed.  It is just part of the calculation.  But you may want to look at your changed circumstances to consider if there should be a child support modification.  I suspect our firm is not alone in having a free initial consultation on questions like this.