When we married, my husband and I decided on a joint bank account. The problem is that we have very different attitudes towards money—I'm careful about spending, while he thinks nothing of blowing hundreds of dollars on a new kite surfing kit. I recently suggested that we deposit money into the joint account and then each have a separate account for personal use. He felt insulted, saying that problems arise because I am tight with money, not because he is irresponsible, and I should treat myself now and then.
Moneywise, your husband has one foot in the marriage and another foot in perpetual childhood. He feels entitled to have what he wants whenever he wants it. It's nice that he can afford things, but such self-indulgence is likely the product of unfinished business from his past. Of course your husband wants you to treat yourself; that would justify his treating himself whenever he feels like it; plus, it proves (to him) that the real problem is not his self-indulgence but your cheapness. Better to blame you for his overspending than own up to the selfishness of his sprees.
Consider your husband's acts financial infidelity. He is not giving all he can to the marriage and is undermining the quality of the relationship according to his whims. Money is just about the most emotionally loaded matter that partners face—except that they rarely face the deep assumptions that money stands for.