Lexie and mark from greys anatomy starting from the plot in season 8 y/n is Lexie Grey, Meredith’s half sister. After the break up Lexie and mark have had a lot of tension. but with marks child Sophia with Callie and Arizona. mark slowly moved on with a new girl named Julia but they are not serious lexie is not under that impression though. Lexie was also with Jackson but they have now broken up. They are both slowly moving on (Sophia is only 1 year old at this point)