looking a gift horse in the mouth

I have an issue where I push too hard to be equal in all things. This leads to me asking to reciprocate oral sex when it is offered even when my partner just wants to give but not receive.

It leads to her being upset that I don't just want a blowjob. I do very much want and enjoy the blowjob but I feel bad in just taking.

Overall when we have sex it is amazing and I definitely take care of her needs but when oral is offered my responses are viewed as being less than 100% satisfied with the offer.

We have discussed it and I know I shouldn't look a gift blowjob in the mouth but I can't stop myself sometimes. How should I discuss or just shut myself up in my brain and just accept things don't always have to be tit for tat?