Lately, Hilary Duff seems to have two things on her mind: her figure and her former flame. The squeaky clean teen queen is the new cover girl for both Us Weekly and Seventeen, sharing her "diet secrets" with the former and chatting with the latter about her breakup with Joel Madden, who may or may not be awaiting the pitter-patter of little feet with Nicole Richie.

Duff, 19, who shows off her ultra-toned, ab-tastic stuff while posing in a bikini for Us' first annual swimsuit issue, reveals she began watching her waistline four years ago after she read an unflattering article about her weight.

"It made me obsessed," she tells the magazine of the criticism that prompted her to count calories and hit the gym -- a lot. "I would beat myself up if I had some fat."

But when Hilary went from cutely curvy to scarily spindly, her older sister Haylie cautioned her to exercise some moderation.

"It was like an awakening," she reveals. "I don't want to be so skinny that people are like, 'Oh my god, she's lost a lot of weight.'"

Duff says she's now satisfied with her 109-pound frame, which she maintains by chowing down on veggies, fruit and lean protein: "As you get older, you just get more comfortable in your own skin."

But has part of Hilary's more contented attitude come from flying solo following her bust-up with Madden late last year?

"I was really happy in my relationship with Joel," she shares with Seventeen. "I was with him from age 16 to 18. Those are important years. He's my first love, so I'll always care about him. But I definitely feel like a different person now that we broke up."

Declares Duff, "And I do feel happy!"

Still, she admits she wasn't thrilled at how quickly he ricocheted into the rickety arms of Richie.

"With the amount of time that we had invested in each other, I felt disrespected that he moved on so quickly," Hilary concedes. "But some people don't want to deal with how they feel, so they cover it up. Rebound! I shouldn't say that. You know what, though? Now I don't care."

Well, maybe she cares a little. Seems Duff is also a wee bit vexed with how the Good Charlotte front man spent his free time after their split.

"All of the going out he did after we broke up sort of shocked me," she says. "Like, that's just so out of character for him, and when we were together, he hated stuff like that, so I felt like I just really didn't know him as well as I thought I did."

Despite her failed romance -- and the recent demise of her parents' marriage -- Hilary has every hope of achieving a happily ever after.

"I still want the cookie-cutter American dream -- to get married, have kids and have a house with a picket fence," she chirpily explains. "I still believe that marriage can work."

Next: Denial File: Diddy & Sienna, Rachael, Posh