I'm not going to help my wife put away the groceries she bought at Costco.
Why aren't you going to help her?
I'll only put them away if she asks me nicely.
It sounds like you don't feel appreciated, but you should help you wife with the household chores when she needs it. She went shopping and it's only fair that you help her put away the groceries that both of you will be eating. It's wrong to expect her to have to ask you in a certain way before you'll help.
Nah, I'll only help her out if she gives me a blow job.
Even though you are married, you should not be expecting sexual favors from your wife. Physical intimacy is an expression of love, not something that you owe to one another. In the same way, helping with chores around the house is simply a sign of appreciation for your spouse, and you shouldn't expect anything in return, much as she doesn't expect anything when she does tasks such as the grocery shopping.