It’s a quandary. My husband does that and I’m not as polite about cutting him off as I was during the first few months. He misses all the cues, so finally I’ll just walk out or tell him to stop talking, then he’ll accuse ME of being rude….. When it happens with others I mumble something about having to be somewhere in 30 minutes and I have to get ready (so leave,) or make up some other BS. Got stuck the other day with a woman who wanted to talk on and on and on and on about her house foundation problems, which led to plumbing problems, which led to doors not closing right, which lead to cracks in the walls…..I guess she thought we were just vitally interested in this stuff. We were on our way to a family event and we just stopped by, so I had a ready made excuse to leave. I really didn’t have to be there at a certain time, but I acted like I did.