If you are breaking rules set in your relationship behind your partners back it’s cheating.

If you and your partner agree to not look at adult magazines and you do with the intention of telling them, its cheating.

If you and your partner agree to not masturbate without the other partner, and you do, with the intention of them not knowing, its cheating.

If you and your partner agree you can have sex with your boss for a promotion and you do, its not cheating. It IS sexual harassment on your bosses end. But not cheating.

Using a romantic AI, or using a AI driven sex robot, or hiring a human sex worker is cheating if your partner feels it breaks a boundary in the relationship. If you can’t agree on a boundary, it’s probably cheating. If you can’t live with the boundary, leave the relationship.

Using romantic/sexual AI == cheating isn’t a yes or no answer. Its a boundary to discuss within your relationship.

Is it really cheating if society can’t possibly consider you and the AI married together? This should be a new class of relationship since it doesn’t fit conventional relationships.

If say everyone has an AI companion, then having them as a life partner from the start doesn’t preclude having a significant other. We should redefine AI not as competition, but as aids