My Husband has ptsd. why does this lead him to have multiple affairs?

There is no evidence to support the claim that PTSD directly causes multiple affairs. PTSD can affect a person's behavior and relationships in various ways, but infidelity is not a typical symptom. It's important to note that individuals with PTSD may experience a range of complex emotional and psychological challenges, which should not be generalized as leading to specific behavioral patterns such as infidelity. Causes of infidelity are multifaceted and can involve a combination of personal, relationship, and situational factors.