It sounds like the lies she has told you have been through omission... and likely because she knew that you would become even more insecure. Or perhaps she was worried about being judged.

From what you've posted, I'd say that you need to work on your insecurities and that the issues in your relationship lie within you, not anything that she's doing.

Like... you stopped being friends with people because she looked at their profile pictures?!? How did you "catch" her looking at their profiles anyway? I've browsed my bf's friends on his fb... some of his friends are pretty hot - male or female! I'm not jealous of the females, and although I find some of his friends to be hot... I'm with HIM!

And the working out... sorry, but you turned that into a contest yourself dear. She gave you compliments while you were trying to improve yourself, and you then have related this to someone she was with in her past. It sounds like it wouldn't have mattered what she said in this situation - if she had said nothing at all about how your body was changing, you'd likely have assumed that she didn't think you were doing good enough.

The other guy's girlfriend messaging her? That shows the gf's insecurity, it isn't evidence that what your gf was doing was wrong - so she's maintained a friendship with someone she had a one night stand with, not really a big deal. If they had wanted more than that then they would have. How did you even know about this?

The fact is, is that she is dating you. Her past is her past, and a lot of what she's shared with you she really didn't need to. But she chose you.

If her past bothers you this much, then you shouldn't be in a relationship with her. It isn't fair to her for you to keep judging her and comparing your relationship with her past. There's nothing that she can do to change her past. She really didn't have to tell you all about her past - it wasn't lying when she chose not to tell you things. If she didn't offer the information, that's her choice. If you kept asking and she chose to not disclose, that's also not lying, it's her not being comfortable sharing that much with you. It sounds like she's had good reasons not to!

All that said, I'm really sorry that you feel so insecure about yourself. But you aren't doing anything to help the relationship based on what you've shared in this post - if anything, you're sabotaging it. She's trusted you with sharing her past - even if it took a long time for her to do so. You're judging her and not trusting her at all.

I'd focus on rebuilding the friendships that you threw away due to your own insecurities. Do you see a counsellor? One might be able to help you work through some of your insecurities. Aside from that, I'd suggest stop tracking everything your gf does on fb because it sounds possessive and a bit stalkerish.

I'm sorry if my post isn't the friendship comfort that you're wanting... but it's how I interpreted your post and I'd rather share my honest thoughts with you. I don't want to see you destroy a relationship with someone you care so much about!