If you are in a serious relationship with woman and threaten to break up her because she never wants have sex why would suddenly start cheating on you?

There is no clear-cut answer to this question, as the reasons why a person might cheat on their partner vary widely. However, some potential reasons why a woman might start cheating on her partner after he threatens to break up with her for not wanting to have sex could include:

1. Feeling resentment or anger towards her partner for pressuring her into sex or making her feel bad about not wanting to have sex.

2. Seeking emotional or physical intimacy from someone else as a way to cope with the dissatisfaction in her relationship.

3. Feeling a lack of power or control in the relationship and using cheating as a way to assert her independence or gain a sense of empowerment.

4. Seeking validation or attention from someone else to boost her self-esteem or sense of worth.

5. Experiencing a decreased level of attraction or connection to her partner over time, leading her to seek fulfillment outside of the relationship.