Are you sure he's not "tagging" her IRL?

Dump him. He obviously wants to be with her, and you deserve someone who fully wants to be with you.

First word that came to mind is ‘gaslighting’, listen to your gut, and leave him. It sounds like he’s already finding excuses to leave you for her “blamelessly”.

You deserve so much better than this. If he won’t commit 100% you need to commit 0% and just leave.

girl why would you put up with this 😂 the bar is so low

Maybe confront her directly and get her side of the story. Sounds like you may be, "the side chick." It is not what anyone wants to hear. But like others have said, it is best to move on.

Girl raise your standards, get rid of his ass. You're miserable, you're obviously the side dish, and he's making you look stupid. never compete for a man, let her have him and find someone that there is no competition

So he tells you he will dump you if you don't stop bringing this issue up, and you keep bringing this up. I'm going to say, cut your losses and broke up. Both of you have issues, you have trust issues and he is giving out ultimatium. Both are toxic as hell traits, and you will probably to better without each other. Personal point my man of 13yrs has no social media, he has never questioned my tags, messages, and photo exchanges with my friends who mostly are male. I have never felt the need to give explanation, and he never asks. And he knows the tags, messages and other content of my phone. I even go on holidays without him or nights out and mostly with male friends and he never bothers me, only when I'm not home at a time I say he texts me to make sure I'm okay. I don't think either of you are ready to take on relationship if you can't even trust each other on simple stuff, or talk openly, and no trust.

Dump him!

So you brought it up again correct? If not, ......... You need to