Coming on here for opinions on whether I am being unreasonable or not...
I have been with boyfriend for 2 years, living (renting) together for one of those. We have been saving for a house. He already earns significantly more than me (6 figures), I earn not even a quarter what he does. We've both been saving equally for the house. He hasn't insisted that I pay an equal share, he is happy to put in more than me when the time comes to it, but I really want this to feel like an equal venture. I have been working my arse off, doing 2 jobs, and I am just about to start a third. My goal is to save £15k towards the house.
On his phone earlier we were scrolling through his photos and he quickly shut the app down once we got to a certain set, became very cagey about his phone. He's never done this before and I did find it suspicious. I am ashamed as I have never done this before, but I have gone back on the photos app since he has gone to bed. I noticed a withdrawal on a betting site for £25k. I know he dabbles in gambling from time to time but wasn't sure whether a withdrawal meant he had won the money or had paid that into it. I am completely naive to any of this, and I don't like gambling. It turns out he has won £25k.
I was obviously shocked and stunned, I then went onto his WhatsApp and he has had a conversation with a friend of his (who also gambles). He has said in the conversation that he doesn't want me to know because I will expect him to put some of his winnings towards our house 
. He also owes one of his family members a significant amount of money and said he doesn't want to tell me as I will encourage him to pay the family member back.
I have never asked him for money, and always tried to pay my way. Whenever he has paid for expensive things I have always offered the money back, but he has told me to put it into our savings. He is generally a very selfless, kind and generous man. He has paid for expensive things and is never a shirker or tight with money. I love him and share everything with him, and I thought the same of him.
I understand if he wants to keep the money for himself, but I don't like the secrecy and assumption I will demand he spends the money in a certain way. I've never asked him for money and I am running myself ragged trying to save up which he is very aware of. I also feel it makes me look like an idiot and fool in front of his best friend who knows all about this. I also feel partly upset, because if I had a massive windfall like this, I would be over the moon it could mean we would buy our house faster, get a nicer house etc. I would be thinking of it as 'our' money. I've told him that when we move in I am happy for us to have a contract stating we have both put 'X' in. I am by no means a money grabber. That does hurt me a little, but more so the fact he is keeping it a secret from me but happy to tell his friends.
AIBU?