So the poor sod has deleted Instagram because you won’t stop going on at him and accusing him and now he’s wrong again because you want him to download it again so you can replay the game?
Why are you even looking at his phone or Instagram? He is allowed total privacy and should be able to set up a phone password and keep every bit of his scrolling to himself. Just the same as conversations he has when he’s away from you, what he watches or reads when he’s away from you, who he looks at in the street or at work when he’s away from you. None of this is your business.
We can marry someone and expect fidelity and honesty but we don’t own that person and have NO RIGHT to interrogate them or check their phones.
Do you ever consider that your relationship would be so much better for both of you if you gave him some freedom? Don’t you think he would appreciate that and you’d see a stronger relationship and probably more affection? Maybe try it, even if it hurts you to do this at first and makes you want to go off on one. Don’t allow it. Do something for yourself when that happens, go out for a walk and let those feelings disappear. Remind yourself that he is a good man and he loves you (he must do or he wouldn’t still be with you). If he’s struggling with his mental health, he’s not going to give you all the affection and be thinking about you but you’re causing some of those mental health issues. Allow yourself to change and you will both be happier.
If it was me, I’d have him set a passcode on his phone and promise that you will not check his phone again and won’t ask about his viewing habits. It takes time for things to change and for a while, your body is going to want to know what’s happening but take yourself off and distract it. Do not break that promise. Let him have freedom and show him some love and affection. I’m sure you will receive a lot in return and you’ll see him becoming well again and feeling better.
And whatever has been said on here about searching for people on Instagram, please forget all that. Don’t go and dump all this on him when he’s home. It does not matter. It doesn’t make him a cheat or a bad man. He has stuck by you and loved you, he’s apologised when he didn’t need to (repeatedly by the sounds of it). Allow yourself to draw a line under it this afternoon and surprise him with a new wife. Both start again and lead the life you both deserve.
Post with updates but let them be positive now. People can help and support you.