I find it a bit odd , but Hubby could be one of those people who leaves the social arrangements to his other half .
My ex would make conflicting plans constantly because he :
1) Was incapable of saying No to any and all invitations from various friends and family .
2) Had no concept of time . Dinner with Fred and Ethel ? Sure ! Then a movie with the Simpsons ? OK ! Joe wants to meet up for cocktails ? Sounds good ! - All of this on a single weeknight , when we both started work at 6:00 AM the next day.
3) Routinely accepted invites , then promptly forgot them until roughly 30 minutes before we were due to be there .
I put my foot down the day I discovered that we were expected at a christening , a company picnic , dinner with his parents , his nephew's Little League game and a buddy's birthday party
all on the same day .
Clueless , he wuz ....

.
Until the day we parted ways , all invitations extended to him were RSVP'd with " I'll have Chibi get back to you on that ."
I say go ahead and call her . Tell her that her husband passed on the phone # . You can express your delight at finally getting to meet the DW such a __________ friend of your husband's . ( I left the adjective up to you !)
Let her know that her DH mentioned dinner . She will probably take it from there .
Also , speaking from experience , the King should find out if Friend's wife is aware you will be calling . That way you don't have to picture her holding the phone at arm's length and muttering " Who the hey is this , and how did she get our number ? "