Xavier Reeves is an artist who was dating Aria's mother. He actually met Aria first and the two had a brief romantic interest in each other. After Aria found out he would be dating her mother, she stayed away after he revealed his less than stellar character. When Aria finally told Ella about Xavier's sleaziness, she kicked him out.
In "Wicked", Xavier meets Aria at his opening exhibit in an old farmhouse. The building is populated with truly artsy individuals, which impresses Aria a lot. She stares at a painting that appears to be nothing more than a nipple. Xavier sidles up to her and asks her opinion. Trying to utilize all of her knowledge and understanding of art, Aria gives a rather abstract description of what the painting could mean. Xavier laughs and says it just looks like a nipple to him. Aria gives in and agrees with him. She laughs about the painting with him and flirts a bit until a woman comes over and asks to borrow Xavier for a while. Aria's surprised and a bit embarrassed that she broke the golden rule of discussing a piece of artwork in front of its artist.
A few days later, Ella is getting ready for her date. She told Aria and Mike that she had made a profile on an online dating site, and she got a match with someone named "Wolfgang". Aria gives her a full makeover and she's still finishing her preparations when the date arrives. Coming down to answer the door, she is surprised again to see Xavier. Upon looking at him more closely, she realizes he must be in his thirties and not a college student like she initially thought. Ella asks how they know each other and Aria gives a vague answer of meeting at his exhibit. Ella is shocked and delighted to learn of his identity, and it seems she's taking a liking to Xavier already. Aria, happy that her mother is finally moving on and enjoying herself again, makes sure to avoid speaking to Xavier out of awkwardness.
When things become more serious between Xavier and Ella, she brings him along with her kids to the family's favorite restaurant for dinner. Aria remains silent and sullen throughout the conversation, wishing she were anywhere else but here. As Mike leaves the table to take a phone call and Ella goes to the restroom, she's left alone with Xavier, who tries to make conversation. Eventually she opens up and figures she could still be friendly with him. They hold a competition to see who could draw the most detail in one minute. Using the provided drawing mats and crayons on the table, Aria draws an old man sitting nearby; Xavier compliments her and reveals his own drawing of Aria herself. Flustered and uncomfortable, Aria then receives several texts from the second "A". She receives two images of herself and Xavier looking like a couple in the restaurant along with a warning note. Aria panics and quickly leaves the restaurant, Xavier's drawing of her in hand
One morning she comes down for breakfast to see none other than Xavier at the table with Mike. They have a nice chat and he offers to drop her off at school. By that point, Aria thinks everything between them is resolved, making her worry less about A. However, a few days later, Xavier kisses Aria in her family's den. Aria pushes him away and runs up to her bedroom. A is nearby to capture the kiss on phone and texts her with a crisp "Gotcha!"
At the Hastings-hosted fundraiser for the school, Aria sees Xavier nearby. She gives him a brief greeting and rushes up to Spencer's bedroom. Xavier follows her while drunk and is convinced she's sending him mixed signals and sexually teasing him. Aria threatens to tell Ella, to which he responds that a story can be turned around very easily. Unwilling to ruin her mother's happiness again, Aria stays with her father Byron and Meredith until the end of "Wanted", when she tells Ella the truth about Xavier. Ella is disgusted and promptly kicks Xavier out of her home. She misses Aria and asks her to move back in; Aria agrees.
"Busted. And by the way, the painting really is a boob." -Xavier (after his identity is outed to Aria)
"I really do know how weird this is, you know. My mom started dating right away after she got divorced. I hated it." -Xavier (while driving Aria to school)
"Actually, I have a secret for you too. I really like Iceland too. I said that stuff to get on Mike's good side." -Xavier (recalling the conversation they had about Iceland in the restaurant)
"Don't try to turn it around and act like this is my fault. And anyway, if you were truly freaked out about the kiss, why haven't you told anyone about it yet? Why is your mother still taking my calls? Why is your brother still inviting me over to play more Wii with him and his new girlfriend?" -Xavier (while cornering Aria in Spencer's room)
Xavier: "Okay. If that's how you're going to be. But know this- I'm not going anywhere. And if you know what's best for you, you won't say anything to Mom about what happened. You know how easily things can be twisted around, and you're just as guilty as I am."