I'm sure someone here has been in the same boat. I've been flirting with this girl who is in a long distance relationship that she is admittedly unhappy with. What are the ethics involved in seducing this girl?

I feel like I should have an honest discussion with her and ask her to either break up with the boyfriend or ask for an open relationship, but that would require me telling her that I like her, which goes against one of the fundamental tenants of game.

What do you guys think?