OP, you're not helping with the point if you won't say what it is!
Re the technical adultery if he meets someone and sleeps with them. Yes, it is. But in the modern world, most people don't care. When it's over, it's over. Your petition has gone in, there is no point in even thinking about this.
Now re looking at his statement. Meh - my XH was a lying cheat and I felt no guilt whatsoever about looking at his post whilst we still lived together post split. Helped me discover £3K that he was trying to steal from me as it happened - a statement he actually tippexed and photocopied! So yeah, you shouldn't look at his post but - I just can't get worked up at that. But I can tell you that my solicitor said it's very hard to use in court something you shouldn't have access to.
But - for disclosure you will see 12 months of statements.
Now there's no hard and fast rules when it comes to financial settlement.
On the face of it, there's nothing unreasonable about him buying new clothes and spending on entertainment.
But if you're a low income household and all the savings in the world you have are £700, then you can say that you want his post split spending taken into account.
Similarly, if you split up with zero credit card debt, and it the 6 months it takes you to make a financial split proposal he has spent £2K on Match subscription, clothes and restaurants for dates, then you are quite at liberty to say "and I will not take £1K of that debt in my half of the settlement".
Everything is negotiable - everything.
If this is your point - him spending large amounts post split - then talk to your solicitor. It may be worth a warning shot that you intend to take account balances at point of split as your numbers for the division of assets.