Wow, just WOW...
I shouldn't, but I can't help myself....
Again, for about the tenth time: This is not about who does or doesn't wish to attend parties with their spouse. This is completely off base and off topic.
Again, for about the tenth time: This is not a 'work' event for co-workers. The invitee's in question are not coworkers. At this point they are 'friends' who continue to stay in contact and socialize with each other because they choose to do so, as friends.
This is a SOCIAL event... A party given by the wife... where a personal (not work) achievement is being celebrated with friends and family... I am assuming that almost every one of these family and friends have been invited along with their spouse... EXCEPT a select few.
NOT OKAY, not by any standard of etiquette, anywhere.
AND to that last line.... (my bolding above)
Plan a party, hoping that others my choose not to come to celebrate with your spouse, because they may feel offended or uncomfortable with having their spouse excluded, so that one may save a little money...
Sorry, but I simply cannot believe the number of threads here where there are sticky situations where people are excluded from parties/celebrations and are possibly hurt or offended because the host(ess) is just not willing to plan and to budget appropriately.

There have been several of these threads here in the past few weeks and months alone.