Also, I think if you are honest, after the 1st call when you didn't hear back from your H, you were using the sitch with your son to make a point. I will tell you flat out, I did it with my D's. The "I need your help and it's about our kids!"
You need to be a big girl here and go get your own straw to suck it up. If something happens, of course call. Don't expect a response. See yourself as a single parent with a friend that's really into your kids. Would you be angry at that friend under the same circumstances? I know I wouldn't.
Just sayin'. I've been there done that and bought the frickin' tee-shirt <sigh>.