Is John behaving in a morally irresponsible way by continuing his relationship with Jessica?

John meets Jessica at a work event. After talking for several hours John asks for her number. A couple days later John calls and asks Jessica if she’d like to go to dinner. He takes her to a nice restaurant, they have pleasant conversation, and the evening goes well. He drives her home and kisses her goodnight. A couple nights later they make plans to get together again. This time they go to a movie and out for drinks and snacks after. At the end of the night Jessica invites John into her home and they become more physical, but she stops him and tells him she is uncomfortable with having sex so soon. They continue to talk for awhile and Jessica asks John many questions about what he wants out of life, where he sees himself in 5 years, and whether he wants to have a family. John lets her know that he wants to make a lot of money at his job and have his freedom and that he does not see himself ever marrying or having a family. He then asks her some questions and finds out she does want to be married some day and have a family. The third time they go out she invites him to spend the night and they sleep together. They continue to go out and sleep together. They enjoy each other’s company and have a fun time when they are together. John has told her he does not want to get married and has joked with her, saying, “I’ll be your boy toy, but I don’t want a serious relationship.” She has told him she hopes to get married and have a family some day and he suspects, although she hasn’t said so, that she continues to hope he will change his mind, even though he has told her he does not want the same things.