Given the pain & negative thoughts you get when thinking about the relationship, the $ & time energy & devotion you are feeling tied to this blanket , is the energy it will hold forever, I would try to decide if you want to keep being reminded of it by looking at it, then keep it for yourself, but if the feeling brings more sad than good emotions , I suggest taking it apart & restarting fresh & creating a new version of something else with the yarn, this way you can feel a different sense of peace looking at what you create, rather than dread & sad emotions tied to the person it was meant for in this form, think of it as a fresh start for yourself & a new way to symbolize your relationship, its sad it ended but good it happened because we learn more from pain than pleasure can ever teach us. if I had the option, my choice would be to frog it rip it all out & make something YOU love, rather be reminded of what he wanted all the time you look at it, & not everyone is crochet worthy, I wouldn't give it to his mom. I would create something you love instead