I have to jump in here about that OW being physically between you thing you said, Emily. I'll tell you in advance this is harsh post.
Now, as for the OW being "physically between" you....that's a load of crap and you need to get a GRIP on that! Remember what I told you about her being LESS than the dirt on the bottom of your shoes? Yeah? Well, she is. You wouldn't toss your dirty shoes onto your bed would you? Or onto your kitchen table? No. You knock it off at the door. I want you to have done that before your husband gets home tonight.
If you keep on, you are going to become one of those women men laugh about in bars. The pitiful women that can't let anything go & constantly drag up the past because they aren't mature enough to see past the ways in which THEY were affected....
You HAVE GOT to understand that in your husbands case....and many other's too.....I doubt that his little fling had ANYTHING to do with you. It was all about HIM and all about SEX and it could have been ANYONE or a FREAKIN HOLE IN THE DAMN WALL. She didn't get into his heart, Emily. She got into his pants. That's why he's on the phone with YOU at night and coming to see YOU this weekend. CUT THE GUY A FRIGGIN BREAK. He's been wasting away in a classroom to get the training that will put him in a better job so he can take BETTER care of his family. THAT'S YOU. YOU have got to grow the hell up and be his SUPPORTER. That doesn't mean that you put up with him screwing around. You shouldn't ever do that and if he did it again he should find his crap packed & on the porch. It means if you will take the steps to broaden your vision and if you become like a sponge and learn all that you can about marriage and how to be a good wife, you can make that man NOT BE ABLE TO WAIT UNTIL HE GETS BACK IN OFF THE ROAD EVERY DAMN TIME HE LEAVES. I SWEAR to you it can be like that. But you HAVE to put in the grunt work first.
One more thing about OW....WHY THE HELL do you insist on giving that piece-of-crap-sorry-excuse-for-a-woman so much power over your life? HE IS NOT WITH HER, EMILY. HE IS TRYING TO GET BACK TOGETHER WITH YOU. She's history.
If you don't cut it loose, you will be too, because your husband is in no way emotionally equipped to have to prop you up when he barely has the tools to prop himself up.
You need to work on your stuff, on your own time. Not when he is visiting. And you know that means? It means you suck it the hell up and bite your tongue this weekend and take care of your husband. Don't you dare make this man put in another 40 hours trying to pacify YOU all weekend.
Emily, put in the time and effort. Be his port in the storm. THAT will make the biggest impact on your situation.
She's dirt on the bottom of your shoes. If you can't scrape it off, throw the damn things away.
You AND YOUR HUSBAND are moving on to bigger and better things from here.
One more thing Emily. Cut YOURSELF a break. His A was never about you. And no matter how "pretty" that hosebag Cassie might seem to you, I'm telling you, no one is as beautiful to a man as the mother of his children.