When a partner cheats on you, it can make you second-guess pretty much everything about yourself. And if you already had low self-worth to begin with, finding out that your other half was willing to sabotage your relationship by sleeping with someone else can completely crush you.

But it doesn’t have to be that way – your self-esteem and self-confidence don’t have to depend on what anyone, even a partner, thinks of you.

Just ask Shanai Martin, a 19-year-old student, who, instead of wallowing in self-pity when she found out her man had been unfaithful, decided to take matters into her own hands and make a positive change in her life.

Shanai, originally from Wales, very dramatically went from a size 16 to a size 10 in just nine months after breaking up with her cheating boyfriend. She has admitted to feeling a great deal more confident following the huge change she made to her lifestyle.

Learn about the woman who lost 200 lbs when she found out she was pregnant:

In fact, Shanai was so proud of the amount that she lost, entirely on her own, that she tweeted about it, including an impressive before and after photo.