I [23M] had an argument with gf [23F] over the topic of oral sex. Can you please prov

We have been in a relationship for 9 months So when I give head to my girlfriend, I do it out of my own genuine interest and without the expectation of head in return. So a lot of timesm, I have done things on her and never got head in return, which is fine by me. But when my girlfriend gives me head and finishes me and then I dont give her head or finger her to finish her, she gets upset and says that she feels left out. So I asked her that if it was okay for me to have a similar expectation which is the expectation to receive head or handjob from her when I felt like I needed one. She said that its not okay for me to have that expection. So I said to her how is it fair for her to have the expectation and me not be allowed to have it? She said why am I viewing it like a transaction to which I said that if anything it is her who is viewing it as a transaction and not me. So she said that it is a gender thing and that in most relationships, the women dont give has many blowjobs as they receive head, so I should be okay with receiving head whenever she feels like giving it. Now I want to make it clear that it's not like I would suddenly wake up and be like give me head. If at all I do expect it, then I would ask it in the right situation itself which would be in the middle of making out. I want to know your views on this. Is she manipulating me into never having expectations while she gets to have all of hers?