Why did my partner vote to leave?

After the 2nd world war, to encourage peace the EU was created. Britain joined in 1973, when I was just 3. So basically I don't have a concept of Britain not being a part of Europe.
In 1995, Austria became a part of the EU. In 1996, I went over to Austria to work and met and fell in love with Gunter Hollenstein. I was able to stay there without a problem, open a bank account easily, be taught German, have a job as a singer and a dancer and sometimes barwork too, all easily because we were united. Gunter came with me back to the UK to live and to work, he easily got a NI number, he easily got German speaking jobs and a bank account. I went on to broadcast the traffic and travel news for ten years and we had Joshua and Elijah on the way. Then Gunter and I decided to open a coffee shop in this country and for a while we had two coffee shops in this country.
Then one day, somebody decided we should have a referendum about something that I thought had already been decided in 1973.
So, I went along and voted. Gunter is Austrian and wasn't meant to be able to vote but he had a polling card and his name was on the list at the polling station. I told him he'd better vote, just in case he is allowed and he did.
We are living history, that is why both sides of the debate feel so passionately, that I can see but what I don't think I'll ever understand is why an imigrant in the UK would vote leave, after enjoying all the freedoms that EU gave him.
Why would a man with two sons in Britain and two sons and a Dad and brothers, sisters and lots of family in Austria vote for the UK to leave the EU?
Being in the EU was a strategic idea to keep the peace, that worked. I still do not understand why my own partner would vote leave. I wish I could.
At the moment I am in bed with flu, I'm calling it the Flexit virus because it bowled me down on Friday when the Leave win was announced.
Illness always makes me think things through and think about life and I've been mulling that one over big time, I can tell you. When I saw the online petition stating the grounds for a second referendum, I thought that it was a very good idea. I posted it onto my Facebook profile to encourage a friendly discussion but generally leavers accused remainers of 'Throwing their toys out of their pram' and 'Childish-like tantrums' and yes my glee was delightfully childlike when it was revealed in the press that the petition was started in May by a Leave campaigner, in case the vote hadn't gone his way!
Like many others, I am left wondering why a person so close to me voted for something that would tear his family apart and give his two youngest sons less opportunities than they ever had before.
Hey, forget the 2nd referendum petition, the poll wasn't run properly and no one is even admitting it.
The truth will out in the end but at the moment each one of us is living with this great divide, this great rift and one day, when people read our history they will wonder why we let it happen and how it came to pass.