Advice required

So long story but to keep it short i found out in December about my boyfriend cheating on me from him. Apparently it happened a few times over the course of our 4-5year relationship. I was going to break it off but he asked for two months to show he could be a better boyfriend and make it up to me. Fast forward 4 months (april) and he hasn't put any effort in, he doesn't plan anything and anytime i bring up him cheating he goes mad at me for ruining a good night etc. A few days ago i seen group messages on his phone to his friends, where they had screenshot my recent insta and were making fun of it, his friends commenting on my appearance. He didnt stick up for me, in fact he made a few comments himself. I don't know where to go from here

I would address the issue with him and question why he didn’t say anything while his friends were making fun of your post. See what he says and go on from there. Tell him how you feel and what you expect him to have done in that situation.

Just ask yourself what do you get from this relationship.
Answer emotional pain, ridicule, lack of appreciation etc.
If you want someone to value you, value yourself first.

He clearly does not value you.

Start saying no to this abuse, cut him off and start over.
No boy friend is better than this boyfriend better described as a bad excuse for a human being.

I did address it with him and he said he didn't realise how bad it was or that i would take it so badly. But the messages were very obviously disrespectful so i don't know

What did they say? Don’t write it word for word if you wish for anonymity.