HELP can't seem to stop the relationship from crumbling

Sorry this ia going to be rather long but i really appreciate and need your help. I am so confused. My partner and i have always been really good together. Its not been perfect but we have always been best friends and really do enjoy eachothers company. Im not saying its been all roses but the bad times made us really strong. We have been living together for 2 years now and like i said its been great. He got a new job, paying more money and i was so happy for him. Anyway the job hes got are all boys and theres a really great moral there. They go out to the pub and away together and what not. My partner never really had that. He is about 2 months into his new job and they all went away for the weekend. Now i know i was wrong and trust me i regret this but on the day before he went we were in bed watching something and he got a text to go to the pub. He of course jumped at the opportunity. When i said i wasnt happy about it he called me controlling and left. Early the next day he left with the same boys for the weekend. He called me 4 times tbroughout the first day but i ignored him. At the time i thought let him get on with it. Anywah i didnt speak to him which i am well aware was wrong. He got back on monday very tired so when i came home he was asleep. I was livid and went to my mums for 2 nights. I know this qas childish and probably the root cause of this. Anywah wenesday i reached out to talk and he agreed. I got home and waited but he didnt show he was in the pub. We had a medical emergency with his family memeber and he came home and we delt with that. Next day he comes home from work tired. We start to talk but he was angry with me and we didnt really get anywhere. I decided to leave it and no more running away. Anyway the next day he went to the pub again and i was home he came in and it was awkward but ww got a take out and went to bed - didnt really say much. I tried to make plans for the saturday and he said he was tired and wanted to stay in. I agreed. Last minute he calls me saying hes going out to the boxing with the boys. I knew there was nothing i could say so i said to do what he wanted to but i was hurt as i tried to make plans and he didnt want to do it. We then said we would do something sunday. Now saturday i was really hurt and the whole week i have felt so uneasy and sick as this isnt us. He caught me crying said he loved me and he was just making bad decisions. I said i want us back to how we were he gave me a big hug and said we would be. So i rang him after the fight - he qas drunk and on route to a club. I said i thought he had no money he said he didnt. He ended up hanging up on me. I sent a text awhile later telling him i loved him, if he needed anything let me know and i was looking forward to our date day,etc and to have a good night, etc. He read it and didnt respond. At 6am i rang him again he was round his frienda drinking. He told me he loved me, itll all be okay and we will talk when hes home. He came in at 11am this morning. He has been so distant. I understand hes tired but i was just trying to talk normally with him. He ended up saying under hia breath im making him want to go out and he wants space. I let him sleep got him breakfast / coffee but all day he hasnt wanted to speak to me or be around me it seemed. I wrote him a letter explaining how much he means and me not wanting the arguments or atmosphere. That i just want us normal and back to how we were. That im happy he has friends to go out with and what not. That our rekationship means more to me than pettyness and that i was sorry for anything i had done in this. He hugged me and said he loved me and went to bed. Im hopeful it might go back to normal but scared if it doesnt. I dont want this to mess up and thats it for us. I love the bones off him. Advice needed