Went out for some drinks and one of DP's 'best friends' from a previous workplace (who I've never really liked) started really criticising DP, and then practically asked what I'm doing with someone like him? Referring to the fact DP doesn't have a degree, is 'punching above his weight' looks wise, and likes plain, simple food, when I'm a massive foodie. Note; DP is coeliac and is quite cautious about food/eating out so hardly his fault.
The reason I don't like the friend is because he's rude, arrogant and stuck up and he's always putting everyone around him down. To be honest I think DP thinks he owes this guy friendship because he's been supportive in the past with work and career stuff (he was slightly more senior). Ultimately I think he's jealous of DP because he's happy, successful and popular - this is because he's a kind and good person, and this guy is not.
Do I tell DP? How do I tell him? He knows I'm not a fan of this friend so don't want him to think I'm trying to split them up or something. (I really like and get on with pretty much all of his other friends).