>I am yet to see on the screen a heterosexual man
>and his lesbian woman-friend
A relationship like that won't last, because a "lesbian woman-friend" would soon grow tired of constant "I know you said no, but I still want you to reconsider that threesome" suggestions.

No reasonable screenwriter would suggest such an improbable (or, rather, hardly possible and volatile) realtionship. It wouln't feel believable, although again- if you really wanna see that on screen, keep checking those whacky shows on TV... maybe, just maybe...