Good post Elegran.
I did find retirement hard at first and actually found the helpful "you won't know how you found the time to work" comments quite irritating. I had worked since the children were tiny, travelled a lot and worked long hours in a demanding and stressful job.
We moved from the busy south of England to deepest rural France where absolutely nothing happens in winter. We had lots of building and gardening work (still do) but the bit of me that was used to planning, organising and delivering major projects was left a bit adrift. I soon came to realise that the ex-pat circuit was not for me and although I now have good French friends in the village, it took time for those relationships to develop. I taught part-time in French schools for a bit, served on the local council and had a few private pupils, but I gradually came to resent the need to be in the same place at the same time each week.
After nearly ten years I have learnt to develop something I never had before which is the ability to be content within myself, to watch the seasons change, to spend time doing nothing very much. I spend the majority of my time growing, cooking and preserving food, reading and getting exercise in the beautiful countryside round here. We have a couple of holidays a year and visit our children in the UK and Spain.
OH has never struggled at all with retirement; I did, but I think I have found my equilibrium now.
I think what I am trying to say is that contentment doesn't always have to come from outside activities and "busyness".