I wear glasses.
I have student debt that gets paid every month from my DH's salary.
(My debt is ONLY student debt, and it was taken on after we were together and with DH's agreement, so it is a little different.)
So I'm pretty close to being in the same situation as the OP's DH.
There is no way on earth I would EVER even CONSIDER spending hundreds of £ on myself without consulting DH.
If I got a little extra money through overtime, or a bonus, and I thought "you know what, this is extra, money is so tight, let's have a little treat"
I would NEVER think that the only person who should get the benefit of that treat was me.
If he was such a great guy he would have made sure the "extra" money bought treats for everyone. Hell, they'd have a lot more treats every month if they weren't all paying off his credit card debts.
And I'll say it again: unless his glasses fell off his face into the sea (this actually happened to me this year), he HAS glasses. He might WANT new glasses, but he doesn't NEED them right now before checking whether his wife might need something more.
And even when my glasses fell off my face into the sea and I had no other choice but to buy a new pair, I STILL consulted with my husband, the person who shares the financial burden of running our household, before buying them.
This man ran up debts when he was single for no good reason. That often speaks to a sense of entitlement to "treats" that takes no account of what can actually be afforded.
The fact that he would drop that much cash without even considering the needs or wants of his family (who would be financially better off without him) shows that he has not changed. He has learnt absolutely fuck all from all of this.
Instead of learning the lesson that his profligacy has put his family at a disadvantage, he has learnt the lesson that other people will take the pain so he can treat himself.
This is a serious problem, that needs to be tackled properly.