I second the comments made by GG. You are already sounding like you want to own the mistakes you made in your M which is truly great. One thing to remember though - she made mistakes too. Sometimes I find it useful to remind myself of that as it helps me moderate my thoughts and not beat myself up so much.
The declining spark was one of the reasons my H gave when he moved out, too. I can definitely see how I contributed to that…but he also has some responsibility for maintaining the spark and I can't really identify anything he did to try to improve the situation.
G
H 37 Me 36 Together 15 years Married 5 years No kids BD Apr 2014 H moved out 2 Jun 2014