Your Comprehensive Guide to Alex's Romances on Grey's Anatomy

Olivia and Alex share a casual fling before she decides to break things off with him in order to pursue George. Unfortunately, she contracts syphilis from him, which she passes to George. In season two, they start having a sexual relationship again, much to Alex's then-girlfriend Izzie's dismay. Years later, they have the world's most awkward reunion when he treats her kid, with Jo learning about Alex's syphilitic past.