Ryan Shazier is a "liar and a cheater" ... this according to his wife, who just put the former NFL linebacker on blast by sharing raunchy text messages she claims he sent to another woman.
Michelle Shazier -- who has been with Ryan well before his career-ending spinal cord injury in 2017 -- unleashed on her husband in a since-deleted Instagram post on Wednesday ... saying, "A person that loves his family … this is what they do to their family … the WIFE.. that has been there for him since day 1!