My bf has a best friend of over 25 years, who is also 20 plus years his senior. They met when bf was in his 20s and the friend was 40 plus. The friend has never had a relationship and is gay. This isn't my bfs only friend of course, he has other close groups of friends that he goes on boys weekends away with (they are all in their late 50s), but his friendship with this guy is different. They go on weekends away with each other and the friend's brother and his wife, the trips are arranged by the friend. The friend lives in his home town abroad and my bf will catch up with him on visits home which I understand but the friend recently arranged a standalone dinner for again my bf and the friend's brother and wife which the friend paid for; I wasn't invited. On one level this is a very long standing and clearly dear friendship, but I feel that the friend treats my bf as his partner, making up a group of four. I have raised this with my bf who down plays it and says because his friend has poor health (he has long standing health issues with no impact on ability to do things) they have only a few years left. I haven't met the friend, he hasn't visited. We have been dating 8 months. It's really beginning to grate and I don't know how to deal with it. The 4 meet up at least twice a year and my bf sees the friend I would say on average for a long weekend a further 5 times...