Hmm...I think it would have been more accepted if the GF at some point noticed purple was becoming smitten with MC first, and then the GF allows them to become closer....because she wants to make her man happy.
But to have purple make inappropriate passes at MC's GF without his knowledge, will affect some who dislike the use of a predatory lesbian trying to instigate a throuple relationship path. It makes the GF a shitty cheater if she allows it to happen, especially when she is pregnant with MC's baby. Purple should be interested in MC first, not his pregnat girl friend.
But I guess with this dev's previous history it's been always OK that girl on girl content happens without user consent...but for many it's the same if it was guy trying to have sex with a love interest. So I guess I'll wait to see how this title ends, avoiding any of the previous disapointments that has happened with dev's other titles.
Happy New Year.
Regards.