Hey dad, you're a fucking dick. Plain and simple. Who would want to even talk to their friend, knowing they are potentially going to be fucking their dad later? This has nothing to do with age, and everything to do with invading your daughter's personal life, and destroying her friendship. Dick.
Any adult over the age of 18 who uses the phrase "I'm a grown man" obviously isn't. Dad needs to grow up, ditch the gf, apologize, and get some therapy.
http://dilfthemovie.org/
http://dilfthemovie.org/