One of my best friends whom I've known since college was invited to the wedding of her friend from study abroad, which took place more than a few years ago. My friend was originally going to go with her boyfriend of (I think) 6ish-8ish months. I think they already RSVPed, the wedding is in a month, but I'm not positive. But my friend recently broke up with him. The wedding is in the city I live, and as my friend lives about 3 hours away, she asked to stay with me a few weeks ago. I was exited to see her, as it's been a little while, and said yes. I was on the phone with her the other day, when she told me about the breakup (which she confessed was a long time coming), and she expressed a lot of anxiety about going to the wedding alone. She wanted to go, but the only person she knows at the wedding is the bride. I wanted to make her feel better and jumped in with "well, if the bride okays it, I'll go with you." When I asked, my friend said the original invitation said "and guest", and that she spoke to the bride and the bride was fine with it.
The more I think about it though, the more I worry that I encouraged my friend to be rude by putting the bride in an awkward position of okaying a "substitution", particularly if my friend remembered wrong and the invitation was specifically addressed to her and her bf (I know that etiquette says it should have been). At the time, my rationalization was the bride must know that my friend doesn't know anyone at the wedding, didn't know my friend's boyfriend, and according to my friend, invited her with an "and guest", so it must not have mattered who the "and guest" was, and I didn't want my friend to feel badly. I realize this could have been misguided thinking. Ultimately, the damage is already done (if it was damage), but I'd like to get your opinions for future reference, especially as I'm entering that time of a million weddings.