Re: So angry at husband right now but don't know what to do...
Here's what I'd do. Go to marriagebuilders.com and read about the program - how it works, why it works. Download the Love Buster questionnaire, two copies, and ask him to fill it out. Tell him that you want to improve your marriage and that means making him happier. If he won't, do your best to do it for him with what you know. You can fill it out if you want, if you think he'll be amenable to reading it; you may want to wait til you've done the steps, though, so he's more receptive.
Once you know in what ways you Love Bust him - such as the last-minute planning - you make a concerted effort for at least two months, to stop ALL the things he lists that bothers him about you (within reason). It takes that long to break your habits.
What this does is remove stress from the marriage. It takes away his reasons to be irritated, and his need to complain about you to her.
Then, after a couple months, download the Emotional Needs questionnaire, and both of you fill it out. When you find out what his top 5 ENs are, you again make a concerted effort to ensure that you are ALWAYS the only person meeting those needs (within reason; if he likes motocross and you're afraid of bikes, you can go support him while he rides with his friends; but you are supporting his EN; see how that works?).
Finally, you should be spending 15 hours a week TOGETHER, doing non family/household things - in other words, you should be dating each other. Go on walks, play a sport that HE likes sometimes, go out to eat, go to movies, take a class together...you need to invest in your marriage and protect it by YOU being the person he thinks good things about; and that comes with spending time together and getting out of your rut.
After a good 4 to 6 months of you doing these three steps, you should see a marked decrease in his attention to her.
If not, then they're having an affair. Because the way they are talking to each other is EXACTLY how affairs start.