Killer FedEx driver Tanner Horner went home and had sex with his fiancée just hours after he kidnapped, sexually assaulted and then murdered 7-year-old Athena Strand , a jury has heard. The  confessed murderer made the sickening revelation in a twisted attempt to deny being a pedophile, according to forensic psychiatrist Dr Eileen Ryan, who interviewed him in jail several times after his arrest over the little girl’s 2022 slaying in Texas. “He had sex with his fiancée,” Ryan, a defense witness, said under cross-examination Wednesday. Delivery driver Tanner Horner has pleaded guilty to kidnapping and strangling 7-year-old Athena Strand outside her home in Wise County in 2022. FOX 4 DFW The twisted 34-year-old had allegedly told the psychiatrist he slept with his partner soon after the killing in an attempt to prove he wasn’t a pedophile — even though he admitted sexually assaulting the helpless 7-year-old girl.…