No, Winston Smith is definitely not married. In fact, marriage is something that is presented in this novel as being yet another social institution that has become dominated by the Party and the all-seeing eye of Big Brother. There is no privacy and you are not allowed to have or foster your own emotions for anybody else without Party approval, as this is seen as a distinct threat by the Party. Consider how Winston and Julia struggle to keep their illicit meetings secret. In fact, the whole novel, from the very opening, stresses the way that Winston seeks to hide himself and what is really going on inside of him from scrutiny:
Winston kept his back turned to the telescreen. It was safer, though, as he well knew, even a back can be revealing.
So although a major section of the novel is Winston's relationship with Julia, it is important to remember that they are not married and that their relationship breaks all the rules of Party members and is one of the reasons why they are both arrested and tortured.