All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
We did not understand what you meant by your statement "Is this the same as saying divorce"; if you meant that if this expression is of the same value as saying divorce, the answer is that a wife saying to her husband that she will not observe his rights unless he fulfils her rights is not considered divorce, as divorce is only in the hands of the husband. Even if a wife says to her husband 'I divorce you' and the like, this statement is of no value, let alone other words of less importance.
As regards the narration which you mentioned, it is reported by Abu Daawood that 'Abdullaah Ibn 'Abbaas narrated: "The people of the Book (i.e. the Jews) used to have intercourse with their women on one side alone (i.e. lying on their backs). This was the most concealing position for (the vagina of) the woman. This clan of the Ansaar adopted this practice from them. However, this tribe of the Quraysh used to uncover their women completely and seek pleasure with them from in front and from behind, and laying them on their backs (but all in her vagina). When the Muhajiroon (the migrants) came to Medeenah, a man [from them] married a woman of the Ansaar. He began to do the same kind of action with her, but she disliked it, and said to him: "We were approached on one side (i.e. lying on the back); do it so, otherwise keep away from me.” This matter of theirs spread widely, and it reached the Prophet . So Allaah, the Exalted, revealed the Quranic verse (which means): {Your wives are a tilth to you, so come to your tilth however you will}[Quran 2:223], i.e. from in front, from behind or lying on the back. But this verse meant the place of the delivery of the child, i.e. the vagina. So, the revelation confirmed what the husband did. Nonetheless, the narration did not mention after that whether or not the woman accepted her husband's request. Nevertheless, the wives of the companions used to accept the Islamic rulings. Moreover, we have not come across any narration which clarified whether or not her husband divorced her; in principle they remained married and did not divorce.
There is no doubt that the wife is ordered in Islam to obey her husband and fulfil his rights even if he is somewhat negligent about her rights. The narration which you mentioned in the question is authentic. The Prophet said: "If I were to order anyone to prostrate to someone else other than Allaah, I would have ordered the wife to prostrate to her husband." [At-Tirmithi] On one hand, if a wife is disobedient to her husband, he should follow the steps of treating a disobedient wife which are mentioned in Fatwa 89480. On the other hand, the husband is obliged to fulfil his wife's rights as she is obliged to fulfil his rights, in this regard please refer to Fataawa 83157 and 88304.
Finally, it should be noted that both spouses should be keen to do whatever leads to the stability of the family [and marital life] and avoid any reasons of dispute, and be wise when some problems happen in order to avoid any unpleasant consequences like divorce and the like.
Allaah Knows best.