Seems like she wants a baby and a commitment to me. Maybe address those first.

There could be something going on that's bothering her. Maybe she feels insecure, or maybe she's stressed out, or maybe she's tired, or maybe it's a hormonal thing. You've mentioned talking to her about wanting to spice things up, but have you talked to her just about how she's feeling and what's going on in her life?

if a women posted this about a man everyone would immediately agree with her. FYL for having a partner who doesn't care to meet your needs or seemingly even try

How many times did you use the phrase "moist panties?" That'll usually send them running for the exits!

id bring up that it makes you bored or unaroused when sex is super basic. religion, culture, trauma can all affect people's sexuallity and she may not have the confidence to talk about it openly. i think maybe communicating about why she shuts down when you're trying to work on being more sexual with her which is what she is asking for. whatever that issue is, being sensitive and non judgemental, open about your insecurities i believe can help. i have sexual trauma from childhood and it affected my sex life in my first marriage greatly. sex should be fun with your partner you trust and love, not boring or traumatic. hopefully you 2 can get to a sex life that your both fulfilled and enjoying. good luck !

I can think of several possible explanations ranging from sad to problematic… (1) It could be GF was raised on the idea that anything except reproductive sec is “dirty” or “wrong”. That’s sad… (2) It could be that GF wants a baby and you are the designated sperm provider. That could be problematic if OP is not ready for a child… (3) It could be that GF is afraid she’s already pregnant with another man’s child and needs someone who will help raise the child or pay child support. That’s tragic… OP, be very, very careful if you aren’t ready for a child especially if this is new behavior.