I thought this was an interesting read. I've read a lot of her articles and I felt this one, in particular, could be helpful to some users on here. She's talked about her toxic first marriage openly and while she states she believes you can manifest an ex back she thinks in some cases you shouldn't, especially if they are abusive, toxic or just plain horrible in general. 
She also lists some good questions to ask yourself before you decide you want the ex back. 
Here's the link to her article. 

http://sarahprout.com/manifest-my-ex-back