she slept with what?😏

So today I invited all my friends to come out to my favorite Mexican restaurant for drinks and chit chat for cinco de mayo this Upcoming Friday and I invited all my friends to come. Most of my friends said yes except for for two which are my co workers I asked why they are not going to come and they told me that they didn't want to hang out if my other friend E is going. I asked why not!? And they told me they didn't like what she does and don't want to be around anybody like that. I had no idea what they was talking about so I ignored the whole conversation saying they are being petty and said fine don't come if you don't want to. I didn't want to talk to E about it cause I really didn't want to spark anything cause she has been upset lately. She finally told me that she has been sleeping with this married man and that she has been going through a lot with him so she can't wait to get out and get drinks to discuss everything with me. I felt like that she dropped a bomb cause I didn't know the guy she was dating was married and I really didn't get phased by it. But my other friends (who are married) may not want to go maybe because they found out about her sleeping with a married man and don't agree with it. I don't know how I'm going to handle this situation? cause I know going forward of me having events I am going to want them all there.