I served in the Royal Marines for 22 years and the RAF for 13 years and as ex-RAF I know what you mean! However, most ex-Royal Marines join the Royal Marines Association in their local area, and they meet about once a month at their nearest base. The meetings are held in one of the messes, and we are made VERY welcome. Once a year we all meet up at Lympstone in Devon for a weekend thrash. We have a motto, "Once a Marine, always a Marine", and happily it is true.
It's a shame you guys couldn't experience something similar.