I don't think it's bad that you don't want to whore out your partner. We all have different directions we want to take our sexuality.
I had a partner that was a pot head and after 5 months together, he lost his job. We had done the anonymous cum dump game for a while and he got off more on searching for guys in the area and organizing the event while I got off more on being the cum dump. About a month and a half after he lost his job he started taking cash and weed from guys that he let breed my hole. It took me about 3 weeks to find this out and only made it hotter for me. It's one thing to be whored out by your partner, but it's another to be "whored out" by your partner. At first I was kinda pissed but after thinking about it realized I liked it, cash or no cash, so I admitted to myself it was all good and enjoyed the ride...literally.
Don't feel bad, just know you're one part of a couple and you both have different fantasies... Don' lessen his joy by bringing in your own doubts.