Have you heard the joke that masturbation is sex with someone you love? Jokes aside though, you didn’t say too much but I am guessing that you feel some kind of guilt regarding masturbation. We hear all manner of things about it, especially if you grow up in Church or go to boarding school. We are told that it causes blindness, that it is a dirty thing to do, that it is sinful, and a bunch of other things.
Touch the clitoris!
I, however, disagree. I do not think that there is anything wrong with masturbation. In fact, I advocate it. The female orgasm is very different from male orgasm if only because our parts are harder to see. The clitoris has a solo function and that is for pleasure. The part of it that we can see is not only small, but it is also covered by a hood. While women have many erogenous zones, the clitoris is by far the most sensitive and if we want regular orgasms, it stands to reason that we should find it and then touch it to figure out what kind of touch it responds to. Some couples find mutual masturbation informative and highly pleasurable.
Is it cheating?
Sexual infidelity means participating in sexual encounters with a person or people who are not your partner and without your partner’s knowledge. Some people do not mind if their partners kiss their close friends on the lips, others take great offence.
I would not think that masturbating is cheating per se, but the answer would best be determined by the rules you and your partner have set for your relationship.
Perhaps you and your partner think that you should share all orgasms and any had without the other is a breach of your agreement? Perhaps your partner watches porn to masturbate and that is the real offence? You would have to talk about this with your partner to come to a conclusion as there are no universal rules. If you feel cheated on, then say that.