You feel so distressed about this, but you actually found out some really ordinary things about this therapist (her partner, pregnancy), it's not like some deep dark secret and they obviously do not keep it in secret, posting on FB. Especially if they are married. I think many (most?) people do this kind of "stalking" sometimes, not just about therapists but whoever interests them. Objectively, I don't think it is a big deal at all, it's not like you are spying into something inappropriate that they are hiding from the world, or are threatening them... But probably it is a big deal for you, because of the long-term preoccupation and stress in your mind. If they don't want people to look at their stuff, they should not use social media or ask their friends not to tag them. I personally don't think you are doing anything wrong per se, other than stressing yourself by reinforcing this obsession. Of course you need to take responsibility for what you do, even if it is out of control, but I hope your T will recognize all this! As a T, she must know that many clients get in this mindset.