Personally, I'm a believer in the power of one way contact. After a long enough period of NC, and once I got antsy enough, I'd send a simple, friendly email or text like "Hi, I hope things are going well for you".
No question(s), no big R statements, no pressure for them to even reply. Then just wait and see what happens. This cracks the door just a bit, and could offer some insight as to where they are.
I do believe there is a time for NC, and maybe that time is now for you.
The thing about no contact at all though, is that to me it could smack of "teaching them a lesson", which of course is not the signal we want to send.
M: A really long time. Crisis: 5 years. She's still worth it.
Life is never made unbearable by circumstances, but only by lack of meaning and purpose. -Viktor Frankl