Advice on inviting coworker's spouses

I'd love to get some feedback on this...

I work in a large place and have worked there for many years and in several departments. It's too large a place to invite everyone, so I initially had 6 people on the list (plus their significant others) that I'm SUPER close with and I told them to please not talk about it at work or mention they were invited. Ideally, I would love to invite everyone, but we're at 175 and footing the majority of the bill ourselves.

One of my coworkers (who is not on the list) was asking me about my wedding plans. She very nicely asked if I was inviting people at work and I said no, since we're footing the bill. She was very nice about it and said she completely understood. She mentioned that when she got married she invited everyone in our department (about 15) people without their spouses. She said one coworker said 'my husband said he'll give you a better present if you don't invite him'

She explained her reasoning-- coworkers wouldn't be able to enjoy themselves and be relaxed because they would be too concerned with making their significant others feel comfortable. I agree with her, as having been a guest at several of my FH's coworkers weddings. It makes sense to me...

Thoughts? I don't want anyone to be bent out of shape, but not inviting the significant others of the 6 people I have on the list would at least allow me to invite people in my department, which I'd like to do. I know some people say that it should be all or nothing as far as coworkers are concerned, but I work in a big place (200+) and there are a few people that I'm close with outside of work.

Sorry that was long! Thanks in advance!