It's difficult to say what you should do in your situation but in some ways its probably reassuring that there isn't a definitely right answer. I would say though that if something hasnt made much difference then they may be value in trying something else.
I remember a while back we had a conversation about whether your H mirrored rather than withdraw/pursue. It might be worth looking back at some if that to see what was working or not.
There's no rush to do anything right now though, but a simple friendly message could be good.
Other than the boundary, would OW change your feelings on what you do for you?
Both mid 30s, 2 young kids BD 7sep14 XW moved on long ago, now living with OM1 D paperwork in progress