Emotional cheating?

My husband and I have been together for 10 years. We got married last year. About a year before we got married he was texting another woman from work. He admitted he did have some feelings for her but nothing happened outside of flirting and texting. So I forgave him. She moved offices and they haven’t talked. (When it happened, I was checking his phone records, I know crazy). Anyway, fast forward to now. We are about to celebrate our first wedding anniversary. The other day I was bored and I was playing with his phone. Usually not a big deal. We don’t have passcodes. So I come upon the WhatsApp (an app you can text on and it’s secret) and I see he is messaging someone under “moms cell” well I knew it wasn’t his moms cell. It was someone else. There was a picture of a woman with her kids. So I knew he was talking to another woman. So I actually just tried to be calm about it and ask him. I asked and he said that’s my moms number. I said no it’s not. Then he proceeded to call it (knowing she wouldn’t answer) to prove to me that it was his mom. Well I told him I knew it wasn’t her. So finally he admitted it. He said it was a different woman from work. I was shocked that he would do this to me. We have been together so long and I would never dream of doing something like this to him. He said they are really just friend. It wasn’t like last time. I told him, okay then stop talking to her and stop being untruthful. We bought a marriage book and have been working though it. So last night I was on his phone and I saw her number. He lied AGAIN. He said they are really just friends and he didn’t think it was a big deal because we’ve been good the past 2 weeks. I go ballistic basically. I made him sleep on our spare bedroom last night. He texts me this morning basically saying he has a problem but they truly are just friends. He just moved offices a few weeks ago and this woman is at his old office. So he said he just likes talking to her to hear the latest gossip at his old office. They even talk on the phone. He said he stopped talking to her when I found out for like 3 days and then he starting talking to her again. He talks to her on the way home from work on and lunch. Then he walks through our house doors like nothing is wrong and that we are a happy couple. I just don’t understand. I honestly believe this woman is a friend. (Could just be naïve) but why does he have to lie and be so hurtful to our marriage? Even if they are just friends, why not just tell me that from the get go? Why continue talking to her after found out? Why claim I’m the most important to you and still do that? Why act like you’re willing to do anything to save our marriage? He says he wants to go to counseling. Would you consider this cheating?

I know what I should do. I know I should leave him. I just don’t want to. Idk if it’s afraid of being alone or because we’ve been together so long. Or what. I want to fix it. I just don’t know how I could possibly do that.

Anyone have advice? What should I do? What can I do? Anyone been through something similar?