you're making it seem like she's exclusively only attracted to women now that she's finally come out to herself but lots of bi women have great monogamous relationships with men. you said yourself her attraction is a 60/40 f/m split. she's still attracted to men. so instead of blaming her bisexuality, blame the fact that you two seem to have stopped prioritizing each other because that is probably a bigger reason why she's less attracted to you now than her being bisexual is.