I also think that 3.5 could be defined as detach, love unconditionally, be compassionate, and eventually, when the time is right, move on.
I think this is honestly the first time I've quoted myself!!!
And now I'm changing my mind ... that isn't 3.5 ... it's #5. Because it comes after #4. Not before.
PEI- I agree with you that this is #5. For over 3 years, I did my best to understand my H and have compassion for what he has been going through. I finally got to the point where I had to move on for me. I believe it became unhealthy for me to accept everything on my H's terms...him having the relationship when he wanted it and then he had no commitment or obligation when he didn't. I made the decision to put an end to the relationship a couple of months ago and at least for me, moving on is difficult too but I feel better about me now. I truly admire people who have the patience to indefinitely be a #4 but ultimately you have to do what is right for you.