Partner had messages from a co worker

I need some advice on whether im in the wrong here, or im mad?

I went on my partners phone and he had a watsapp message from someone at work, he has started back there 1 week ago..after he left the company a year ago but has now returned. The message was asking him if he was ok. I checked my partners phone the next day to see what he had replied, but he had deleted these messages and there was a new conversation. She had messaged him back at 2am about work related things but not important. It was ***** about another colleague. He had replied, for her to be replying at 2am.but he had deleted the message that night. He had further messages thst day with her in the morning whenhe was on the way to work(where she works) and then throughout the day whilst they was at work. Still talking about the same colleague..whilst the messages were not flirting etc.. he still deleted messages, he sent a x at the end of each message..and did not mention any of it to me. I had a problem with this coleague last year when she messaged him saying shes there if she needs to talk..and he replied to her then.

Hopefully this makes sense..sorry

I felt down about these messages, i know it may seem small but i look after our 9 month old baby at home all day and i guess things become bigger than they are?

Anyway i mentioned to him these messages i had seen , his first reaction was you went on my phone? I reacted and said everytime i loook on there, theres something to see. And then it escalated from there

I have seen stuff previously..liking pictures, saying he will go to some ex colleagues house party and also checking someone out whilst with me but i seen him doing it and he later admited it.so i have some reason to be a little paranoid

Since i have mentioned it. He said he was done with us. So i packed up his things and told him to go then as i csnt speak to him about anything. He went back to his mums and has not made any effort at all since then..its been 4 days now. He has cslled me lazy, crazy and ive embarassed him at work. I feel even more angry now him saying this as he has been at his job 1 week and im an embarassment. Do i sound unreasonable here?

I will not stop him from seeing his daughter of course not, i just need another opinion on this situation?

He has gone back to his mum countless times. Id say every 2 weeks if not more, i know i packed his things for him to leave but only becsuse he said he was done. He always says its over, so this time i took a stand and said go then and take your things. We cannot communicate now as every message turns into an arguement. I dont know what to do