Where exactly is my "waist" point?

As I try to upgrade my wardrobe, Ive realized I have absolutely ZERO style and knowledge regarding this. Ive recently lost 30# and want to tone up now. I still have a bit of a beer belly thats probably going to take time to tone. That said, my jeans are always just below my gut. My wife said my jeans look like I have a bag of ________ errrr… a bag or rocks in my pants. The backside looks too baggy. Ive since switched from relaxed fit to straight fit which made a big difference, but wife still says the same thing. Im wondering if Im just wearing my jeans too low? Meaning Im buying the wrong waist size? Im 32×30. They fit great and look great IMO minus her comments 🙂

So #1 – should I be measuring my waist size someplace else? and #2 – what about for more formal trousers? Where do I measure?

Thanks for any suggestions. Im learning and making changes. Already feels great.