I’m so sorry you’re hear Frizzle.
This is not true:
I feel like he has made me feel because I don’t give him enough attention or affection or sex. That that’s why he went looking somewhere else.
You are not at fault for his decision to cheat. That’s something that you need to understand very clearly. He cheated because he wanted to. He cheated because there’s something the matter with him, not because there’s something the matter with you.
If he was lonely, he could have told you so. If he wanted more attention or affection or sex, those are things married couples need to discuss from time to time. If he was really unhappy he could have asked for counseling then. Or for a separation. You get my point - he had plenty of moral and honest options. Instead he saw someone in a bikini at the beach, flirted with her and got her number. No part of that is your fault.
No marriage could work otherwise. We have to choose to be married to our spouses everyday. Can you imagine being in a marriage where if you screwed up somehow - weren’t affectionate enough, or too tired for sex - that justified cheating? No way.
His friend that he went to the beach with - that guy’s an accomplice. That guy is no friend to your marriage. Is he married? Did he also meet someone at the beach? Maybe his wife ought to know. Either way, I’m not sure your WH can remain friends with him and regain your trust. How often do they pick up girls when they’re out?
Same question for the AP - is she married? If yes, then her husband needs to be informed. See if you can find out without your WH knowing. If you contact the OBS (other betrayed spouse) and your WH finds out about it, you’ll know they’re still in contact.
Speaking of which, he should send her a no contact letter.
Make sure to read the articles in the Healing Library here, there’s a lot of good information in them.