Dilemma dilemma

Hi. I am 43 and have been living with a man 8 years younger in my house for the past 5 years. He has a problem with his temper when we disagree that results in angry outbursts, swearing, insulting me and silent treatment that can last weeks. It is very upsetting behaviour that has led to us nearly splitting up many times but we always end up staying together. Things then go very well for a while, then he gets angry about something sooner or later and we're off again. Last February, I gave him an ultimatum that he gets help to fix it or we split. He saw a counseller and he did fine right up until December, then angry outburst again, this time in front of friends on a christmas night out. He never ever apologises for any of it, and blames me for 'setting him off'. We argued about it this weekend, as I said (again) that I couldn't live like that any more, always wondering when it was going to happen again, and also with his habit of being on the computer with headphones on all evening, every evening. I feel lonely and fed up most of the time. I asked him to stay somewhere else for a week so that we can decide what to do. He was distraught but did go. My family live a long way away and we were planning to combine our finances and move nearer to them this year but I am now questioning whether that will work following the reappearance of the temper. Last summer, I had some work done on my house to prepare for selling up and got very friendly with the builder. He is married with children and I was in my situation so there was never any talk of a relationship but we have become very close, exchanging texts, which are sometimes racy, and meeting up whenever we can during the day just to see each other and chat. We have slept together a couple of times and it is amazing in an emotional as well as physical way. Please please don't judge us. I know it's wrong. We have admitted to each other that we love each other but that nothing will ever come of it. My partner got my phone and read my texts at the weekend and understandably went ballistic. I have convinced him that it is just a deep friendship and nothing else has happened. I do feel awful for lying but, as I said, I was feeling unloved, ignored and in complete complete confusion about what to do now that the emotional abuse has reappeared. My dilemma is this: if my married friend was single, I would choose to be with him over my current partner without a second thought. Because he isn't, is it fair to get back with my current partner almost as a second choice? I do love him and we are generally happy but, as I say, I would pick the other man if I could. Is it fair on my partner to have him back when I know he isn't my first choice? He would be devastated if we split. Any advise would be very welcome as I just don't know whether it's fair on my partner but I know that if we move away, and if he can control his anger, we could have a happy enough life together.