Girlfriend won't swallow
My girlfriend and I have been dating for a year, and I love her very much. We have a mutually fulfilling sexual relationship, and we communicate well. Recently, I told her of my fantasy of her performing oral sex on me and swallowing my sperm. She said that would be "gross," and has never brought me to climax during oral sex because she does not want me to come in her mouth. I perform oral sex for her, and I enjoy having her sexual fluids on my face and tasting them. We have discussed sexual fantasies before and have pleased each other very much. But she will still not accept my sperm in her mouth, and I feel like she does not want to accept a part of me into her body -- that she does not have the fullest desire to please me. When I first asked her to do it, I expected her to want to pleasure me, to have desire for my penis. Now, I feel like she thinks my body is not desirable. My question is: what must I do or say to make her change her mind, to make her understand how much I wish she'd do this?
Perhaps you could look at your experience in two ways: your girlfriend could agree to go down on you, and you can agree not to ejaculate in her mouth; or, if she already goes down on you, accept that this may be enough for her right now.
There are probably many reasons why your girlfriend chooses not to swallow your semen. Some people worry about possibly not liking the taste and/or texture. You could ejaculate, and both of you could do a taste test. Others worry about gagging and vomiting, or getting sexually transmitted diseases (STDs). Ask her about these thoughts with an "I want to learn" attitude. Similarly, you may think about gently expressing to her not just what you want, but what it means to you. Communicating in this manner will not guarantee a change in her behavior and needs to be done without that expectation; however, it could foster greater understanding, and even intimacy, in your relationship.
In the meantime, you could focus on all the ways your girlfriend shows you that she cares for, accepts, and loves you, rather than on what you are not getting from her. You have probably noticed that the more pressure you place on her (or anyone), the more she will run away from what you would like her to do. Be aware of, and respect, her wants and needs, while still acknowledging your own. Similarly, when you go down on her, do it because you want to, not as a proof of your love, or as a trade-off, or investment, in what she might do for you in return in the future.
"Accepting your sperm in her mouth" is not a test of love. It is a sexual behavior that your partner does not choose to do at this time. This does not mean that she does not care for you, nor does it reflect her desire to give you pleasure. However, swallowing sperm is pretty high on the intimacy scale. Nancy Friday wrote about this in her book, Men in Love - Men's Sexual Fantasies: The Triumph of Love over Rage.