I am going to keep from telling my parents about my long distance partner coming to visit.
What is your reason for wanting to hide this?
I don't want to talk to my parents about this, we have fought about this issue before.
I understand why you'd want to avoid bringing it up then.  Parents should avoid being judgmental about the partners of their adult children.  They should be more accepting!
I'm going to pretend she didn't come and not talk about my sex life in front of everyone.
It makes sense why you would be upset with your parents for not accepting your partner. It is probably a bad idea for your parents to try and dictate who you have a relationship with as this may just make you want to be a rebel. Either way, it could be a good idea to talk to your parents about how you feel in this situation.