Q&A Is ‘Rubber Necking’ or Blatant Attention to Other Flirtatious Women Part of Infidelity?

My wayward husband says that his blatant behaviors with other women in front of me while I’m with him is not infidelity because it’s not a secret. Once again he is telling me this is a “marriage issue” so it’s not his responsibility. I feel as if he’s implying it’s my insecurity that is causing problems in the marriage and possibly implying my insecurity has brought about the infidelity. My response to him is just “ok” as I realize he is doing his own work and I can’t control the process. But I’m confused about where my boundaries need to be with his behaviors.