My married gay cousins, and all the married gay friends I know, will refer to each other as husband. With the occasional "partner" thrown in when dealing with folks outside the family who they don't know well.

The lesbian married couples all go with wife, again with the nod to "partner" depending on company.

I'd forgotten that marriage was open here in Virginia. For some reason I thought it was still on hold awaiting a SCOTUS ruling.

I'm very glad that it is and that they can get married.

but I've heard "husbands" for all men (or grooms) and "wives" for all women (or brides).

I'm busy embroidering towels to give away on The Great Day (when the SCOTUS does the right thing). They say "Mr & Mr" or "Mrs & Mrs." I'm sure people will let me know if that's not acceptable.

he's my husband now. So after the wedding, your co-worker will have a wife. (Sometimes, like when completing check boxes on forms, spouse.)

Different people will approach wedding formalities differently. It was not really important to me to be referred to as a groom for the brief period I was one. Similarly, not all lesbians are going to appropriate the whole "blushing bride" vocabulary, while some will. The best thing is just to refer to them by name. If you don't know the name, it's an indication you are out of your depth having a lengthy conversation about the private life of your co-worker.

Most people will be generous and accepting of a mis-step from a good-willed supporter. It took me a while to get used to using the term husband instead of partner. 22-year habits are hard to break!

Cheers!

And congratulations

Just use the word you would use to describe the opposite-sex spouse of a co-worker with whom you have a similar level of emotional connection.