Friends of Jennifer Aniston say her engagement to Justin Theroux has made her happier than ever, not only because she feels it's such a perfect match, but because the relationship has allowed her to forget her troubles with ex-husband Brad Pitt.

Even though it's been seven years since Aniston and Pitt called it quits and caused a tabloid frenzy, pals said Aniston thought about Pitt often after the breakup, which would upset her and get her down about her love life. But since she's been with Theroux, those issues have largely dissipated.

"She used to think about Brad all the time," a source said. "But these days, he barely crosses her mind. It's like, ever since she met Justin, she has really finally started to get over Brad and what happened in their marriage."

Not only has Aniston moved past dwelling on her marriage to Pitt, but she has also moved to mend fences with him. The 43-year-old actress sent Pitt a note saying she has forgiven him for everything and that she has no ill will against him or his fiance Angelina Jolie, the source said.

Instead of focusing energy on her past, Aniston is enjoying her present and the great relationship she has with Theroux, which she wasn't expecting.

"Jen still can't believe such an amazing relationship has finally come her way," the insider said. "She really wasn't expecting to fall in love, and it took her by surprise."

But now that she is in love, the former "Friends" star is completely head over heels, and she's been telling friends all about the wonderful aspects of her relationship.

"Jen's been bragging about Justin's impressive equipment and says he's the most sensual, erotic man she's ever dated. She says Justin is way better in bed than Brad," the source said. "Justin makes her feel special and treats her like a queen. ... She definitely wears the pants in the relationship, and Justin is happy to let her have her way. He does everything he can to keep her smiling. Jen always says how 'authentic' Justin is. She truly admires him."