Op your situation has really struck a chord with me as i'm struggling with similar myself. Dh and I are married, together nearly 20 years, 3 primary aged dc.
Dh had an emotional affair over the space of around 2.5 months with a woman from his work which ended 3 months ago - and I know her too to make it worse, although we weren't friends. I found out when I discovered WhatsApp messages between them - genuinely, I wasn't snooping at all and looked at his WhatsApp with his permission for a message from our son - and found messages going back a week or so which he'd obviously thought were deleted and weren't.
I confronted him and we had the holy mother of fucking rows. Didn't speak for a week, he was devastated, we decided to make a go of things etc. Then I found another message between them a WEEK later - brief but instigated by him. He was lending her something he'd heared she was looking for or some crap...but it was flirty/bordering on sexual, full of innuendo and inappropriate as it was before.
Had I not found this second set of messages, I think the EA would have continued. But I confronted him again and now I am 100% certain it's ended.
I know what you mean about knowing you're better than the OW - and yes it sounds awful and big headed but that's the case with me too. OW is less attractive/intelligent etc than me. I don't know if that makes it easier or harder to deal with.
Our relationship has been great, even at the time of the EA - he's a fantastic husband and father and I love him so much. I still can't believe he did it. It was at a time of huge upheavel and stress in our lives (probably one of the worst times we've been through really) and he says it was an escape type of thing. Very sorry, loves me, has now blocked her on everything.
Contrary to some of the other posters, I would bet my life on it that there was nothing physical between them - without being too outing, the opportunities/logistics just make it unfeasible and it's the one thing I believe him about. So in your case, I don't think your DH has necessarily been physically unfaithful.
I don't know what to do either. I'm smiling every day and carrying on. We're being normal mainly. We're having sex. The thought of splitting, having to explain to the dc, them growing up in a house without us both here makes me want to curl up.
But I cry every bloody day. I look at him sometimes and i'm so angry I want to physically hurt him. We had a pregnancy scare last month (stupid!). My FIRST thought was of her - that I would have to have an abortion because I would feel so humiliated at the thought of the OW thinking I was a push over and pregnant within 3 months of it all coming out - and how pathetic that made me look, what a pushover. It was a false alarm - but the thought of how his EA had made me feel about my own possible pregnancy (as i'd never have considered abortion before) made me feel physically sick.
Sorry, I've rambled now i've started. Sorry I can't be of much help as i'm floundering myself and have no idea what I want - but a virtual handhold for you. It's shit.