Venice (during shoulder season - not during the summer when it would be really hot and crowded). Amsterdam - English is widely spoken, excellent cultural offerings, great transit system and bike lanes all over the place, and easy to get to many other cities/towns quickly and cheaply on the commuter trains and good high speed train connections to other parts of Europe if you are interested in spending a long weekend (or two) elsewhere. Antwerp - it's got more of a city pulse to it than Bruges (which tends to roll up the carpet at night) - also (similar to Netherlands) the language barrier not as much of an issue in Belgium - and easy to get commuter trains for day trips (or high speed trains for long weekends out of Belgium). If you like a city on the smaller side - and a place with zero language barriers, Galway (again, during shoulder season like June when the daylight hours start getting very long - or, if you don't mind it being a bit more crowded, during the Galway Arts Festival in the summer). Galway offers train service to some other parts of Ireland (ex. Dublin), but they also have Bus Eireann service that fills in the gaps to other parts where rail service doesn't reach. If you aren't completely adverse to renting a car during your stay, you may want to consider more of a smaller Irish village - like Kinvara, across the Bay from Galway (about a 40 minute drive) and right on the edge of The Burren - very peaceful and quaint, yet still has a nice selection of about a dozen local pubs (several of which offer live music on certain nights), a few good restaurants, and a good location to drive around and view other parts of Western Ireland and along the coast (depending when you would stay, you could also consider spending a couple of days and nights staying out in the Aran Islands). For a 2 month stay, you could actually spend 1 month in Western Ireland and the 2nd month in Northern Ireland (Belfast or Derry).
Since you are retired and probably pretty flexible about whenever you want to travel, you might also consider something like signing up to volunteer in a program like Vaughan Town in Spain. They offer locations all over Spain - volunteers agree to spend a week with business professionals from Spain who want to improve on their English conversational skills - in exchange, you get free room and board at one of the resorts around Spain where they host the program (you pay for your own plane ticket to get to Spain). Read the requirements carefully on Vaughan's website - you aren't there to learn Spanish - you are expected to only speak English - and often the days are long and can stretch into the evenings (you are expected to eat all meals with the program participants) and check out some of the videos available on YouTube from past sessions to see if it is something that you would like.