Most likely these mutual friends are not thinking about your divorce or you reading their social media postings. They are just going on with thier lives. They aren't sitting around thinking about how to hurt you by what they post...
If you are that sensitive then unfriend and/or block them. It doesn't make sense to expect them to sensor themselves because of your marriage ending.
Just a thought from an unbiased viewpoint.
I agree with this 100%. It's completely fair to expect mutual friends to be sensitive to your needs if he or she is talking to you directly, but on social media they're going to conduct their lives as they see fit. Do you want them to choose a side? If so, you could try having a conversation with them about it, but I doubt it would go too well.
What was the original post about? In what context was your STBX referred to as a "hero?" It's possible that the context would shed light on the topic and change my point of view (i.e. if you have reasons to believe this person posted that to at least in part cause you grief and suffering).
As others have stated, you'll need to block and/or unfriend them if you don't want to see things of this nature in the future. Another poster suggested filtering out any posts your friends on Facebook make that include your ex, which is a great idea and a nice middle ground.
I can empathize though. As someone going through a divorce, I know how gut wrenching it is for me to see posts that include my STBXW. However, it's important to separate any negative feelings you have for your STBX from the friends that you both share. Immediate reactions of anger, frustration, hurt, betrayal etc. are normal, but try to gain some perspective and realize that your divorce will affect them as well and they'll want to salvage both friendships if possible.
Oh man, this is literally killing me!!!!!! I opened FaceBook to see pics of my ex with someone I considered to be a real good friend. She and I had been texting back and forth thru all of Christmas week. She made no mention that my ex was going to be visiting them and here I open up to pics. I was shocked beyond belief. I CANNOT do this! I text her telling her I hoped we could maintain our friendship in a different way than FaceBook and then I took her off my friends' page, along with the guy that made the post I originally started this thread about. I feel sick to my stomach. This friend knows all the hurt and hardship I have been thru, it's just incredible!
That friend may know, and yes, there is an element of betrayal in that. Without knowing details I can't say anything definitively, but again, your friends are dealing with the loss of your relationship as well. Yes, to a much lesser degree, but if you've both been friends with these people for a substantial amount of time it's normal that they will want to be there for both of you.
I'm in a similar situation, except the mutual friends I've been leaning on don't post on social media. My STBXW and I have had a couple as friends for 10 years. They even asked us to be the godparents of their daughter. Now that everything is heading toward divorce, this couple has had the unenviable task of being there for both of us (more so me than my STBXW).
The week before Christmas my STBXW reached out to them with what I'd call a less than accurate account of the last four months that we've been separated. I was hurt and upset, and some of that was directed at my friends for not sticking up for me. However, I had to take a few moments to sit back and process what was going on—for me and them. We are two people that these friends care about deeply. Heck, I spent Christmas with them. I know that in their hearts they want the best for us and are dealing with their own sadness over the loss of this relationship and the pain that it's caused me and my STBXW.
It's no different for your friends, so if you value the friendships then you'll need to let go of any resentment you have for them continuing their relationship with your STBX. In reality, this is likely misdirected resentment and hurt that is actually intended for your STBX. It's all part of the process of letting go—we can't control their actions or the actions of our STBXes; we can only accept the fallout of our decisions, whatever that may be.
I really hope it gets better for you and you can salvage the relationships you'd like to continue.