When you have a patio visit/In-Room visit how is the conversation, what do you talk about, is it a one sided conversation, do you have pictures to show, is the conversation about things happening now or things in the past (example children are now grown adults and working but the conversation is as if they are still in school living at home), do you ask what they have been doing or is it too difficult for them to recall what they did one hour ago?
Even though my MIL has had short-term memory loss since 2015, it is almost impossible for me to avoid saying "do you remember" in a discussion with her, so you're not alone!
What do you talk about? It depends on where your wife is on the dementia spectrum. If she's in earlier stages and is still conversant, you can talk about most anything, family, weather, current events, etc. When conversation and understanding gets more difficult, forget the current events and weather, do more reminiscing (you can always do that regardless of her stage). Your wife may not remember any recent events but she'll remember her teen years, your dating years, and her long ago life. An old photo album is excellent. Regardless how advanced she may get, always talk to her. It may become more of a monologue on your part but she hears you. And if she can, give her time to respond, her processing information has greatly been affected. In my wife's final days besides reminiscing, I resorted back to telling her what the family was doing, where should we go on vacation, what we'll order for supper and anything else that came to mind. The words don't matter, only the sound of your voice.
When talking wears out, play some music of your and her generation. Did you have a favorite song? Did she like music of the 50s, 60s, 70s? Find a music app on your phone and play those oldies when you visit. Pandora and Stingray are 2 good apps. They have many genres.
And good for you in deciding to attend a support group.