My boyfriend is 41 and is a loner type. I'm his first serious girlfriend. I'm the same age. He has a strong minded mother who is controlling and his father died when he was 15. He lives alone. Through our 3 year relationship 70% of the time he is kind, thoughtful and level headed. However the 30% is not nice. When he gets stressed from work or in the car its as though a switch flicks and he becomes totally intolerant, rude and then shuts down completely. He then ignores me for days even if his anger issues are nothing go do with me. About a week later he is back to his usual self, calm and level headed and acts as if nothing is wrong. He is a loner type who finds crowds and people in general stressful. He has low self esteem and struggles with communication and showing any kind of emotion. He has a lovely side where he would do anything for me but I just can't cope with the black cloud that descends in him every couple of months. He has never seen anyone about this and wouldn't. I'm wondering if he has mental health issues. Thanks for your opinions.