How to enforce no contact after a break up?

My ex (25) and I (24) were together for around a year and a half and we broke up around a month ago because he moved abroad for work and did not want to try long distance. There was a myriad of things that led to this conclusion but the biggest one was that I eventually wanted to get married and he thinks he never will and so there would be no point in trying long distance if we had to break up at the end anyway due to misaligned goals for our future. He had also been in relationships since he was a teenager and he thought it was important for him to be single for a while so that he could learn not to depend on another person and be able to grow by himself for a while. I thought this was logical and understandable and just before he left we had decided to stay friends and be on good terms. At the same time I asked for no contact for a while so that I could process him leaving and our break up and he agreed.

He left and we didn't text for around one week or so when he texts me about how he's struggling in the new country and from then on we have been texting almost everyday. I have talked to a lot of my friends and they seem to think that there is nothing wrong with texting him especially when we didn't have a bad break up and its natural to want to continue to text so close after the break up. But I feel like he's taking way longer to respond back to me (2 days sometimes) and everytime it happens it really hurts my feelings. I keep checking his socials to see who is following and everytime he follows a new girl I spiral into thinking about whether they have gone on a date or whatever (which I had told him I was going to do because I know myself, but that's besides the point). I want to tell him that this is not good for me and I am always emotionally on edge waiting for him to respond and when he does respond and its not what I wanted to hear that's a whole other emotional rollercoaster for me. I don't know how to ask this and I think its partially because I want to be on good terms and I don't want to hurt his feelings but I know its the best thing to do to preserve myself.

I don't know if I should just stop responding to him, or if I should call him or should just text him with my thoughts and stop responding after that. Any advice appreciated, thanks!