Need opinion thoughts..... long story

I have been married to the same guy for 20 years, we had kids after 8 years of the married life. Things started getting stressful and I made the decision to be a SAHM after my second child was born. Things were still going ok unitl last year when my husband started spending less and less time with me and the kids. But overall I always trusted him and thought of him as a good husband and father. My kids started acting up and I was stressed with my daily life which I had conveyed to my husband but he was just too busy at work or so I thought. He would always tell me he was in a meeting and will call back soon. So I kept dealing with the situation as best and I could but we kept drifting apart. The only fun we would have was the vacations we would take together. 2 weeks ago my husband said he would come late from work since he had something to finish. I happened to call him and he picked up he phone at which point I heard a baby in the background noise. When I confronted him to video conference he said he would call me back. When he came home he said he was at a bar with friends and said he did it often without telling me to not upset me. The following week I read an email n his work account (sent to a female colleague) that read. Have some alone time but not sure to call as it is late. Anyway if I don't talk to you have a safe trip and enjoy. Anyway will email you again. LU S. The reply from her read: Hey what happened...no news about you since morning!!!I spent the day working a little running errands. In bed, will watch my show a little bit before sleeping. What time are you reaching? Get some rest. talk to you later....good night. To which he replied later that night: Reached 30 min back. Good night. I will be out and alone between 7 and 9 am if possible call....I know folks will be around so if unable to call thats fine. Do have a safe trip and email when you have time but do email as often as possible. LU Then next morning after she didnt call he wrote again: Probably busy. take care L.....already missing. let me know if possible when in air and when reached. When I confronted him he said there was nothing happening between the two he was just very close to her since she confided in him about personal stuff. And he refereed to her affectionately as love in a flirtatious way but nothing physical happened between them, In other words they were not in a relationship. After I checked the call logs I found he has been calling her after office hours in the month of July also he ash been chatting with her through and app but I cannot see the messages since he cleared the chat. He claims the conversations was him lending a shoulder for her problem. The letter was written on August10-11 and he claims since she didn't reply to his email. it was only him. My problem is I have always trusted him in these 20 years and have no reason to doubt him prior to this. But the call 2 weeks ago and the email sounds like he has been hiding stuff. I don't know if there is any truth that a) nothing was physical and b) this was only 1 sided infatuation and nothing more. What do you think of the situation? SHould I forget everything and trust him?

I've posted a 'similar' question of my own. Feel free to give me your thoughts. You have no choice but to trust him for now but I would keep an eye on things. Sometimes you gut instinct is the right one. It's the confiding in personal stuff that would bother me. She could tell one of her girlfriends instead. I'm not really sure what other advice to give you but I don't think he is being 100% honest with you