Is a wife considered sinful for refusing her husband and not desiring him, due to the reasons mentioned: his failure to provide, his frequent travels and relationships, his stinginess, and his refusal to divorce?

It is the wife's right that her husband provide housing and maintenance. If the husband refuses, she has the right to refuse his advances and seek a divorce.

However, if the wife has no legitimate Shar'i (Islamic legal) excuse for refusal, and she is providing for the expenses voluntarily, then it is not permissible for her to refuse to share her husband's bed. This is because her responsiveness to him is one of his greatest rights over her. She does not fully fulfill Allah's right until she fully fulfills her husband's right. Even if he were to ask for her while she is on the back of a saddle, she should grant it to him.