I could see how a woman would feel sort of hurt if her guy refused to kiss her after she just sucked him off. It's kind of like the guy must think what she did was gross or something. So why should she bother to do something nice for him if he views the act as gross or degrading?!?!??
I believe some of the reluctance for guys might be how he sees the girl sucking his cock. I can remember when I younger I had a new GF give me a blowjob, swallow and then ask me to kiss her. I said no. Now that I think back on it, I probably said no because I hardly knew this girl and I was not in love with her at the time.
But with my wife, who I have a great deal of love and respect for, I find kissing her spermy mouth sexy and erotic.