DP and I have been together almost 10 years. We have a great relationship and love each other dearly.
Unfortunately, we have suffered some very difficult times with a lot of his close family having serious illnesses.
I have tried my best to help and be there for him through all of this, I am very close to his family so it's also been very difficult for me.
I am an emotional person, I easily show my emotions to those close to me. DP is not an emotional person in the same way as I am. He either gets angry about things happening around him or he is very quiet and in a way emotionless... refuses to talk about it or shows he cares, although I know he does. (I hope I'm making some sense)
In the last few days, for the first time during our relationship. He opened up to me a little more and explained how he feels.
In so many words he told me that he cannot express his feelings and hurt but he is anxious about things happening and he feels it's 'odd' to feel this way.
He sleeps well, and can switch off at work, but when home alone or driving to and from work he thinks things he feels he shouldn't.
He said he is forever having thoughts of me and DS being in an accident and dying, he has thoughts daily of one of us being attacked, he has thoughts daily of one us being seriously ill. He also has these thoughts about himself, what if he was ill, what If he died, what if a member of family died etc 
I told him that I believed the amount of upset and illness in his family has possibly caused this and has possibly made him anxious. I am no professional and I have encouraged him to speak to a GP about it but as it took so many years to discuss it with me I don't think he will. He told me that if he told a doctor about all of this he would be told he was crazy.
I know 'googling' isn't the best option but found myself looking up anxiety symptoms today and I am in two minds if this is the issue or not. He doesn't appear to have anxiety issues according to what I read...
Any advice of what I can do to help would be greatly appreciated.