I need some advice

Hi, I have been with my boyfriend for 4 years we have a son together who is 2 and I have an 8 year old son from a previous relationship. Things have never been easy for us and things have always been a bit rocky but we always seem to sort things out and get on with it. Just over a year ago we moved away from London and all our friends and family to give the kids a better life, at first things were good but the past six months I feel like our relationship is slipping away. He works long hours so during the week I literally see him for 2 hours a day, he doesnt ring me during the day he might email to say hello but that is about it, so we have no communication at all. I work part time and the rest of the time I am left to bring up the kids by myself. Our problems started when I found some text messages on his phone that were sexual and to a girl that he worked with, I forgave him but I constantly think about it and I dont think he was entirely straight about and whenever I try to bring it up he tells me to get on with it and try and forget about it, it was a mistake and thats it. I have no confidence at the moment and I am probably taking that out on him but I feel it is his fault that I am feeling like this. I honestly dont know what to do, should I stay with him or leave. Please help!