While I know you are more focused on your lack of sex with CP, the fact that your libido has waned in general may speak to a hormonal issue. My recommendation is a talk and testing with your GYN.
As one of the previous commenters mentioned, bi is on a spectrum. Like you, I had not experienced sexual attraction with another woman until recently. However, I am not attracted to men either unless their minds work a certain way.
I pretty much decided I am attracted to entities with certain ways of thinking, and the outer casing is insignificant. All of that said, I am far more used to interacting sexually with men, so attraction or not, the other is more of a challenge for me. Sounds like you are the same way. So it would be logical that if your libido has waned in general, the relationship between you and CP will the effect first.
What I am trying to say is I don't think the problem is between you and CP - just that given your newness to sex with women versus men, that is where your waning libido is going to show first.