It depends on the jeans. Darker, higher quality jeans are more acceptable, but why go half way? Wearing a suit with the jacket completely open, a couple of buttons undone on the dress shirt or even a v-neck or scoop-neck shirt, and a unique accessory (hat, watch with a leather band, subtle necklace) and leaving everything open is casual without being sloppy.
You can buy a pair of well-fitting dress pants or slacks fairly cheap. High quality jeans can run from just under a hundred dollars to 300 bucks. Even more if you buy from where the denim snobs buy from.
In short, it's acceptable only when the jeans are well-fitted and are made of darker, better quality denim with a good fit, but not optimal.
I think you should have went with the leather jacket with the button up shirt and jeans. Everything tucked in. With the jeans you can have a faux-disheveled look by tucking half of your shirt in. Play around with your look for 10-20 mins before going out. You don't want to look like every stiff out there.
Googled "casual suits" and got this article.
http://www.vinspi.com.au/blog/how-to-wea...-casually/
It goes through different ways to wear your suit casually and has a section on jeans.