That's exactly how my wife is. She'll drop thousands and thousands on travel, her only real passion, and she won't bat an eye at spending a few hundred on a special occasion meal, but anything else, she's tighter than a frog's butthole.
I have a few good stories of her frugality in action, but they're impossible to tell without discussing details of our finances, so I won't. What happens with her mentally is, once money is in an account in the bank, in her mind, that money is inaccessible, almost like it's ceased to exist. Great attitude for saving money, not so much for spending it.
Our cars are old, our furniture is nearly broken down, our carpets are stained beyond cleaning...but she won't buy new stuff until something becomes inoperable. Even if she won the powerball tomorrow and had $500M to spend, she'd still be like that. She'd spend several million on a private cruise around the world, but would drive to the port in her 14yo Honda Civic.
