Well if you think sharing with her will create conflict unnecessarily then its a good idea to minimize what youshare with her. SET - the staying tool works for most relationships BPD or not. You could use it with her.
Youre free to seek counsel from whomever you feel is appropriate. Your friends aren't her business. If she has a problem with her image and her sons marriage she may need to address it with him. It's good to not get in the middle of that.
It's a process - most of us come here in the middle of a storm. It takes awhile to sort through what to do next.
Be kind to yourself. Sometimes its babysteps - it takes time to get to a place where it'd bad enough that you are seeking help, it going to take some time addressing it.
