Hello jomili,

What you are describing is know as a "Blind Carbon Copy", abbreviate BCC. Set this property in the Outlook MailItem and assign your email and your boss's email to it as a semicolon separate string.

Example
  Set olApp = CreateObject("Outlook.Application")
  Set olEmail = olApp.CreateItem(0)
    With olEmail
      .To = "J.Smith@xfoo.com"
      .Subject = "Current assignments
      .Body = "The current job assignments are attached."
      .BCC = "You@wherever.com; Boss@wherever.com"
      .Send
    End With