On the one hand, I actually do seek out partners who are uncomfortable with hiding being poly, even with the sort of lying that is necessary to protect children, other relationships, etc. The fact that they are willing to put others' needs ahead of theirs is something I admire. But--
I had a partner tell me, If poly was socially acceptable, I wouldn't hide the fact that I was in a relationship with you. And I liked that. It showed me that she wasn't dating me out of some desire to "experiment" with the lifestyle...or to try to prove to herself that she was "different" than other people, or any motive other than she liked being poly and liked being with me.
You don't really want to be with someone so callous that the title of "girlfriend" is more important than how it affects the people around her. But you also don't want to be with someone who is actually ATTRACTED to the secrecy of the lifestyle....or I don't know. Maybe you do? Whatever works.