John , Im going through something similar.

I was with my ex for 4 years, and like you she was the best, I share a similar story. The only difference is that it was my family issue which got in the way which caused our split.

we have been split about 18 months now. I have been dating my new GF for about year, Whom has been truly great to me

However Im still fighting the demons and the ghosts from my EX , she is still on mind. I have written to her a couple of times but had no response,  I no im hurting not just me, but my new GF and probably the EX.  my ex is almost like an addiction. to make things worse I have to travel past her hosue everyday on my way to work.  So ig it helps I know the emtions you are going through, ITS hell