<P> Ryan then goes to the beach, and upon discovering the letter, reads it . He finally says goodbye to Marissa and exits the alternate universe . </P> <P> In the final episode, Marissa appears as Ryan's final flashback as he reflects on his life in Newport Beach . As he backs out of the driveway, Ryan remembers seeing Marissa standing on the corner watching as he and Sandy drive away when Ryan thought he was not coming back to Newport Beach (as seen in "The Premiere"). </P> <P> Ryan Atwood is Marissa's second boyfriend on The O.C. Although extremely on - and - off - again throughout the show's course - their relationship originated as a platonic friendship in the pilot episode, which later escalated into romantic feelings . By the 10th episode of the first season, the couple officially began their romantic relationship . The beginning of this relationship sees its first end when Marissa feels that Ryan has overreacted to Marissa and Oliver Trask's friendship . The second course of Marissa and Ryan's relationship fails because of Theresa Diaz and Ryan's illegitimate child together, whom Ryan agrees to help raise--returning to Theresa's arms and leaving Marissa to return to her alcoholic behavior . The third attempt of Marissa and Ryan's relationship terminates after the suicide of Johnny Harper where they struggle to mourn him and need a break from each other . The couple's last attempt at a relationship ends when Marissa is killed by a drunken Kevin Volchok who sends Ryan and Marissa's carr off the road, sending her to her death . </P> <P> The overall relationship between Marissa and her mother, Julie Cooper, is full of angst, rebellion, misunderstanding and miscommunication . Beginning with the fling between Julie and Marissa's ex-boyfriend Luke Ward, the strain in the two's relationship increases throughout the course of the show . After Marissa's father Jimmy Cooper and Julie divorce, Julie treats Marissa as second tier to her many wealthy, successful boyfriends and fiancés in an attempt to save her own social and monetary status . The troubled Marissa is then left to deal with her friendship, alcoholic, and depression issue alone, without the help of Julie . The mother - daughter duo move from their home neighboring the Cohens, to Caleb Nichol's home, to a mobile home during their time of financial hardship . </P>

The oc when do ryan and marissa get together