He asks: My SO (significant other) always posts pictures of me on her social sites, comments or ‘likes’ ALL of my stuff, I’m every weeks #MCM, she has a picture of us as her wallpaper, tags me in anything love or relationship related, loves to dress alike, and she says she just likes to share with her friends & family how happy she is and likes to show what love looks like. Is she showing off to prove a point or is this normal?
HAHAHAHAHA noooooo silly boy, that girl is pissing all over you. She’s ‘marking’ her territory. She constantly shares pictures so not only can any girl that comes around know you’re taken, but so her friends & family can have a GOOD visual of what you look like in the event they see you out in a setting (having too much fun) without her.
I will say you have to IMMEDIATELY IMMEDIATELY stop dressing alike!! Stop it! Stop it! Stop it! You get a pass for Halloween & family photos (same color only). Otherwise you look really stupid, cheesy and like a puppet.
To answer your question: yes she is proving a point, 2 actually. 1) that she has someone, might wanna do a background check, ask around this bird may be bat hell crazy. 2)He is taken & “happy” (rather he knows it or not) Is this normal? Not the the extent you’ve described.
The problem you will encounter however, is if you start blocking her actions or asking her to stop. She will immediately think something is up, she will get upset. So if its bothering you, then you need to take back your personal space, but be prepared for her to have an attitude about it.
You Forgot Your Common Sense 
Well she could just really like the guy. Also is the Marking of territory really that bad?
She could really like him, and with that, innocently enough I think she begins marking because of that. Marking can be that bad only if you’re a private person, OR not that into her/seeing other people. I think when the feeling is mutual its not too bad.