i think my husband is up to something really bad-please help

Im going to try and condense this story but leave all the need to know details
my husband and i have been together for 8 years. We are young with two children. I am a stay at home mom and he works full time. Things have been stressful at home money/Livnig in a fixer upper house/not enough time together etc
we are very involved in our church and our kids are involved in the children's ministry. The pastor is our age. She is in a relationship but her boyfriend lives an hour away. My kids are close with her and i was start I a friendship with her as well (she seems reslly nice/trustworthy but explained she doesnt have a lot of female friends-and has told me things in confidence that are strange for a pastor-but nothing like bad per say.)
About 3 weeks ago my husband began texting this pastor asking for "advice" on his depression. I was not informed of this by either party. I happened to see she was a recent contact on his iphone and when i asked him he immideatly lied and then about an hour later Sao "ok i was" when i confronted the childrens pastor she played the "oh he didn't tell you?" Card but said they had only talked a few times. Long story short. I found out they texted a ton, they deleted they messages so i cant see what about. They also talked on the phone for 30 minutes at a time probably 10 times (i pulled our phone record.) I told the children's pastor please dont contact him again she said "if i saw him in a grocery store i would tell you" to find out the next day she called him at work. I asked her about it she denied it, then called me back 5 minutes later to say "im sorry i lied to you, i did call him. I need him to back my story up to my boss that i was just counceling him" (long story short on that, the church found out knww upset about them talking and her licences could be revoked if i told them i think she was having an affair with him) but why wouldn't she call me? Why is this all so secretive. Now my husband says he is extremely depressed and nothing makes him happy anymkre except our kids. He has completed checked out from me. Won't barley tslk to me, extremely temperamental ans doesn't csre that im upset and wont really talk about the state of our marriage at all other then "we will go to counseling, i cant focus on us until i fix me" i get that but why the lies on both ends? Why the deleting? Why is she talking to him after i asked her not to? I wish there was a way to get the actual text messages back to see what was really being said. My husbands like a different person since i found that they were texting. He has cheated before and i gave him a second chance and the pas to knew this and i feel that she should have told me. I asked her what they talked about she said "his issues,madness,etc" but then eventual after hounding by me admitted he asked her "why is marraige sex only with one man and one women" why would she leave that out when i asked her originally??? A lot of both parties excuses are "i forgot about that" and husband litterally lies until i shove truth down his throat. Something is going on. I cant kick the feeling. I dont want ti believe a women in her position would be so bad. But why has he completely shut me out? It seems like something who has intrest in another man would do. Sorry this is so long. Thanks for reading im so lost.