I've never posted here before - I am diagnosed with BPD-NOS and I've had experiences with it since I was a teen. I'm currently not in therapy since overall I'm very stable but this problem is something I'd like help with ...or God knows what

I get obsessed with someone, completely fixated with and in love with them and they're all I can think about basically from the moment I wake to when I go to bed. Comes with all the usual fun splitting, black and white thinking, loving and hating etc. I'm used to all that, as much as it sucks. Here's my problem: I have a partner, I am married. Right now...I'm obsessed with my friend, and current roommate. I've had these feelings for them for years, basically since I met them...my partner knows it too, he's not in the dark. I try to keep open with him. The problem is I get so focused on my friend, my partner begins to feel neglected. But it's like with this person in my view; I can't notice my partner...it's not fair to him. I don't want to blame my friend, and they cannot move out right now either. It's not their fault I'm mentally ill and obsessed with them - they don't even encourage it. 

I'm just at a completely loss. I can't break my obsession and I'm tired of this hurting my partner. I don't want to cut this person out of my life, they are a dear friend. I just wish I'd stop obsessing and crushing... 