I agree that they appeared to be too chummy. I also agree that if you'd said something at the beginning this had a chance of not progressing. I wonder how you talked with them when you finally did talk. I suggest you let your anger fester and you accused them rather that setting up a way to discuss this. Of course they're going to be defensive and be more focused on their pain than yours. Sounds like you also did not care about how either of them felt.
Having lots of experience with relationships in the past 50 years, i've seen similar scenes play out. I've seen all three people comfortable with it. I've seen wives at the beginning say "cut that out you too." And they stopped. I've known of times when the wife talks with her husband in private.
When the wife said, i'm not comfortable with this. Seeing it hurts me. Or even I'm angry watching this, they have a respectful conversation later during which both people say how they feel about this situation.
Sounds like you accused them of not respecting your boundaries; boundaries that you allowed them to cross without saying anything. When you allow behavior to continue, you're giving them tacit approval to continue. They don't know you don't like this. You may have shown an attitude they may or may not have noticed as being related to what they're doing.
Based on your description of your work situation, I suggest you let things happen, don't discuss them with someone who could help while your anger builds. You described your angry treatment of your husband when you were really angry at your job. This visit started with you already feeling out of sorts. I wonder why you allowed her to visit when you were tense, unhappy, and not getting along with your husband.
I see you as part of the problem. No one is totally right or totally wrong. You dI'd not allow for a conversation about why this was happening and how to move forward. You still think your husband and girlfriend were too intimate but you don't know what their intent was. You didn't acknowledge the possibility you were over reacting. You were not concerned with how they might feel when you verbally attacked them. You are angry that they weren't concerned about your feelings and didn't apologize. The situation became focused on anger. The reason for the anger got lost in your attack and their defensive response.
I suggest your problem is now your relationship with your husband. Thinking about how to treat your girlfriend keeps you from thinking about why this happened and how do I make up with my husband.
I suggest that counseling could improve your ability to know and state your boundaries in a calm way without anger and accusations. I suggest that if you don't understand how this situation came to be, you'll continue taking out your anger on your husband. You'll have more situations that won't be resolved, more reasons to be angry. An unhappy life, for sure.