She’s addicted to laxative?

I just found out that my girlfriend of three years takes laxatives weekly while i’m at work? She swears it’s not an eating disorder and it’s not about the weight; she says she takes them because they make her insides feel clean.

This began at the end of last year though nothing changed, she just said that she’d felt horribly constipated the entire week and look laxative out of desperation. She took a handful at one time and it helped her out, but she said the relief of it prompted her to use them again the next time she felt “bunged up” and now it’s spiralled to where we are now.

I believe her when she says it’s not weight related; she eats and exercises great. I’ve never seen her restrict and her body’s been the same all these years. She’s shutting me out now because she’s embarrassed but what I could make out of this is she’ll act normal all week but then have a clear out day? I asked her why she can’t poop like every one else and be done with it but she says she never feels clean after it? I’m confused