Long distance relationship?

Right so I have been with my partner for just over a year and half. When we first got together we were very happy although we spent a little time together. We get on well with each others families also. He has just started a new job about 4 months ago, and it literally means he works away Monday to Friday and comes home Friday evening. I only see him on the weekend. This has been going on for 4 months. He works all different places so I know he wouldn't be having an affair and I trust him dearly. When he is home, we both stay at my mums house as ATM we are trying to save for a place of our own. When he is home, we literally do not do much as we don't have the money. He will work on Saturday if the work is there. When he is away, we rarely talk. I mean when he worked here I knew he was coming home at the end of the evening so I wasn't really bothered if we didn't contact during the day but now it's like an effort to talk to eachother. He phones me on his lunch and we speak for around 5 mins then he will phone me again when he finishes for about 5 mins then before he goes to bed to say night. I literally feel like we do not communicate at all. I get the feeling that he is only with me because he is comfortable. Away all week, girlfriend on the weekend. I feel sad all the time, I love him and I'm happy when were together but when he's there I am constantly crying and thinking about him. I'm not really sure at what to do? I mean what can I do, I definitely would not tell him to change his job as he enjoys it and i would not want to be the fault of his career not expanding. But I just think this relationship is being fizzled out because of his work? Any suggestions?

Hi just read your post it has a lot of similarities to my own situation.partner works away and lives away I only see him maybe once a week and sometimes not for long at all. It is really hard I find that aswell . I was thinking of writing a letter to him to help communication. Also try to do something fun together when you are together. I've realised I seem to always be complaining when he is here so I'm going to try and appreciate more the time we have together. It's so important with long distance relationships. Talk to each other when you can but try to have fun when you are together :)) good luck x