Help please I looked and now I'm wanting revenge

Hi
I had posted my story on all about him and was not in a good place I'm just at the beginning of this nightmare ! Anyway I had received lots of good advice from people here and decided to take action I'm on anti depressants so struggling to do anything is a challenge ! Well on Monday of this week I discovered he was still on multiple dating sites despite him being so so happy with the other woman!! Well I came off Facebook and gave myself a to do list cleaned and gutted my house etc met friends for lunch felt a tiny bit better !
I don't know why i did it am I weak or something but day 6 I had a peek on Facebook and what did I see him changed his profile pic to a pic of him and her together all smug and happy ! This is the guy that slept with me then told me he was seeing her and this is the guy that's still on multiple dating sites ! What really hurt me to the core and really upset me was that in all the women he's seen even me with 10 year history he's NEVER changed his profile pic to him and the person he's seeing yet this morning he's done just that ! I've read the posts about them not changing and the other woman will be treated the same but now over 6 months and honestly things look great and with him doing that with the picture has he changed will he stay with her and was it me that's why he treated me badly ?!
I'm back again to thinking of revenge why should he get away with it why should they get happy I want to show the other woman the sites he's on and expose him for what he is burst their bubble!!! Anyone had this experience re Facebook with their N