Has her pushing you around to make sure she stays happy, been pretty much the dynamics in the relationship?
Your concern for her may be clouded by the fact you've been trained to make her needs and/or desires top priority. Getting away and staying away from her will, hopefully, give you more sense of a natural balance in life's relationships. This is the time for you to take care of yourself. Get counseling, or whatever it takes to heal from this R and how to break any co-dependency traits or other issues you may tend to develope in R's.
Btw, forget doing and/or buying anything for her birthday, and have a great vacation WITHOUT her!
This all speaks true to me in my sitch
34, xw33 M-10, T-18 2D (8 and 5) Ilybinilwy-1/16 EA/PA- 7/15-present (with my former best friend) Trial apartment-2/16 (also when she considers us separated) W moved out-8/16 W Filed 11/21/16 D final 1/30/17
