Should I email this to my H? Should I draw the line that any relationship outside of work w/ the OW is not acceptable to me?
No, no emails. Get DEFINITIVE, 100% proof first, and then confront him in person (rehearsing ahead of time, out loud while alone if you have to), and then you can follow THAT up with an email to clarify any points you feel need clarifying after the confrontation, or add anything you forgot to address.
And yes, continued contact with an affair partner without the consent of the betrayed spouse is absolutely a continuation of the affair. It's a betrayal.
