Husband as lying to me and having our child lie to me

I was on my husband's phone yesterday and I saw his text messages between him and our second oldest kid. My two daughters are 25 and 12 and then our middle son is 19. He's away at college. He sent our son a text saying "I'm so sorry. Thank you. I appreciate you. I'll make this up to you somehow. " Our son replied with a thumbs up. He said "I really mean that. No dad would ever ask his kids that. You didn't have to but I appreciate you." Another thumbs up reply. Then he said "Please. Don't tell your mom." Another thumbs up reply. I asked my husband what this was and he won't tell me. He just got mad at me for going through his texts between him and our kid. Also a day before I found this my son messaged me saying he's not coming to Thanksgiving which I was sad because his college is 45 minutes away so it wouldn't even be far. My husband has just flipped this around on me saying he would never go through my things and how could I do this. Will not tell me what he's keeping from me.