In the last part of this series, I said that Juliet's obsessive love for Romeo was based on much on what he represented as who he actually was. This is true of Romeo as well.
From the very beginning of the play, we see that Romeo is alienated from the gender role assigned to him. When the Capulets and Montagues fight at the play's beginning, he is the only man missing. His reluctance to participate in feuding and bloodshed is likely a longstanding "problem." Lord Montague expresses his relief in 1.1 that Romeo was not at the street fight. We might say this is only because he is protective of his sole heir, but the sentiment is echoed later by Mercutio, who states that Romeo is no match for Tybalt, the young Capulet lord.
Similarly, Romeo has apparently grown distant from his peers. He seems reluctant to participate in the most obviously misogynist of Mercutio's jokes, for instance. We do see him twice in Mercutio's company, and Romeo does say some sexist things. But, as we learn, he spends much time alone and participates but little in the lords' escapes.
Perhaps the most significant sign of Romeo's alienation is his relationship with his parents-- or, rather, the lack thereof. Not one in the entire play does Romeo so much as share the stage with them.
Because Romeo lives in a prefeminist world, he is not aware that gender roles are his problem, nor would it occur to him to attempt to divest himself of them. Thus, he is forced to cast about for other masculinities, other male roles that he can play. This is where we find him when the play begins: attempting to portray the ideal Petrarchan lover, proving his masculinity through poetry rather than fisticuffs.
Juliet represents to Romeo three chances to escape his current predicament.
First, by trying on new roles and masculinities. By becoming the Suitor and The Husband, and perhaps The Lord and The Father soon thereafter, he escapes the obligation to be The Fighter and The Womanizer.
Second, by transcending social norms. Had Romeo simply wanted to be married for marriage's sake, his family could have arranged that. But an arranged marriage would not have made him more free, only given him another script to act out. His relationship with Juliet, by contrast, is liberating in its secrecy. Because their relationship is secret, they have no need for the elaborate social dance of courtship. Their relationship is honest and entirely free of artifice.
Finally, Juliet loved him before she knew who he was, and because of thier relationship is now also in rebellion against society at large. She is likely the only person in the world who interacts with him as Romeo, rather than as Lord Montague, Jr.
Romeo's relationship with Juliet is certainly marred by sexist conventions, but it is, for its time, a kind of feminist safe space, where he and Juliet can be themselve, not who they have been told to be.