He's at it again..lying, deceitful and talking to other women

My SO and I have been together for 11 years..We have an 8 year old son and a daughter on the way. They're my World. We've had a lot of past issues with him being a liar and talking to other women such as coworkers, his ex several years ago, and random women I don't know from elsewhere. It's been a long road.. The past 6 months I can honestly say I thought he realized my worth in his life and not to take me for granted ever again. I really think I want us to work out and him be a good man So Bad, I've convinced myself he has changed..

So about a month ago, I saw he had a new friend on Facebook(showed up in feed) that I had no idea who she was..When I casually asked him who she was, he told me she just started working at his job. I figured no big deal, though deep down I felt uneasy about it. He said she was training to go to a different store out of town, and told me she had already been relocated when I asked why I've never seen her a couple of weeks later. Well last night, I found out that was all a lie. He had been 'poking' her on fb and messaging her as well, but deletes all messages. So obviously is hiding something.

Shes a manager somewhere else and has been for some time, and apparently comes into his work all of the time at least that's his story now. No one else at his work knows her, so not sure if I believe him but he says she just asked for his name and she volunteered her full name as well..Doesn't make sense how this just happens or why unless he didnt mention he was married, and was flirting with her. I just don't get it. I do Everything for this man and have been faithful to him and just want to be happy..I don't think I'll ever be happy with him though, there is zero trust on my end..

Why does he keep doing this?? He said it was nothing and I need to calm down.. But why hide shit and lie to me about who she is if it's nothing..I'm so tired and broken just want to wake up from this nightmare that's unfortunately my life..ugh 😖