Partner in another city

hi there Eight months ago my partner left me to work in another city. There was a shortage of work where we lived at the time and the place where he went there is heaps of work and the money is good. We have been together for ten years and have had a solid relationship. When he returns home he often receives calls on his mobile, saying they are from workmates etc. I have complained about it as he always leaves the room when he's talking on the phone. Recently I overhead him saying 'dear' and the warning bells sounded. One night I took his phone to look at the messages and there were some from a lady who he said was a lot older than me and there was nothing to worry about. I know he has met quite a lot of people as he goes out socialising. The fact that he has someone sending him texts is making me suspicious. We had a big row over me grabbing his phone. When he comes home he always helps me when I want something done but he is not as attentive as he used to be. He is coming back in three weeks time for my birthday. I am not sure I want him to be here as if I can't have all of him I would rather he stays where he is. We have never had any problem with communication in the past. He has got some problems to sort out and I have always tried to help him and been very supportive. I have put it to him if he wants out that's fine. I have told him that him working away is only temporary; I do not wish to live on my own indefinitely. I am not prepared to be mucked around and just be a convenience when he returns to my city. He's got nowhere else to stay and when he comes he goes and see his son. I have a feeling that he's befriended some lonely woman and she's got her hooks into him. I am in my late 50's. It's only been two days since we had the big row or confrontation and I am trying to remain calm. Any advice out there would be appreciated.