Dear Dr. Frankie:
First of all, you’re not alone. Many couples struggle with lesbian bed death and it’s by far one of the most common frustrations I hear couples in long term relationships complain about (in fact, I’ve written about it before).
Second of all, each one of us is responsible for getting our own needs met—including our sexual needs. It’s not your partner’s job to sexually satisfy you—you are. You are responsible for getting your needs (and yourself) off. That being said, part of the joy of a long term relationship is being able to have sex regularly with someone you like and feeling rejected when she doesn’t want to is absolutely acceptable. No one likes to be told no when all they want to do is have sex with the person they care about.
My first reaction to your question, however, has to do with your girlfriend’s responses: playing games to avoid sex, saying no without clarifying and giving attitude to your very appropriate questions are all very unreasonable.
It’s not okay to respond like that to someone you’re in a long-term relationship with. She is clearly denying something. It could be her feelings for you, it could be her feelings for herself or it could be something else. What is clear, however, is that you two need to talk. The frequency of sex is a very individual need not only for each woman involved but also for each couple. Several times a week may be your preferred amount and once a month may be your girlfriend’s. It’s a thick topic and one that requires empathy, compassion, and honesty by both parties. You two need to negotiate your needs and how you want to proceed with getting them met. If she’s not in the mood, perhaps she would be okay with helping you masturbate or perhaps partaking in a little make-out session? If it’s something more serious, like feelings of betrayal (like you mentioned), or a history of struggling with sex, it might be useful for the two of you to get professional help in deciphering those issues.
One last comment about cheating: Justifying cheating on your partner because you’re sexually unfulfilled is juvenile.
If you choose to go outside your relationship for sex, it is *you* who is making that choice and not because of something your girlfriend did/did not do.
I encourage you to really pay attention to your own needs and either change how you feel about the lack of sexual frequency or change the relationship. You are the only one responsible for yourself and you deserve a satisfying sexual relationship.