My (29m) brother (27m) is dating my high school girlfriend (31f). My wife (26f) does not like this.

My wife Cory (all names changed) and I just moved back to our home town about a year ago. We lived in another city for about four years where we dated and got married; some of this time we lived with my brother Nathan. The three of us lived well together, I think. Nathan has a different lifestyle than my wife and I, so everyone got along great and we shared a unique kind of "group humor".
Over the past two years, Nathan has moved back to our home town, as have Cory and I. He bought a house so we no longer live together, but see each other frequently (through work) and my immediate family is all quite close. I commend Cory often on her ability to mesh seamlessly with my family. They are all warm and welcoming to her, and she is treated like a "found missing puzzle piece" to our dynamic. I do not take this for granted, and make sure that her needs are tended to in this arena (e.g. if she needs space from any of my family members—or all of them—or if she needs to fly to go see her family, or if she needs help interpreting one of my mom's weird texts). Whatever it is, I try and make sure her needs and our relationship as a unit comes before my family. So about 6 months ago, Nathan becomes uncharacteristically secretive with his plans outside of work. He becomes vague about plans and fuzzy on who he's meeting up with. And through a series of clues it came to light that he was more or less dating Michelle, my high school girlfriend.
Our home town isn't a buzzing metropolis, and Nathan has always been choosy about the girls he's interested in. Namely, they must be of moral upstanding (religion is important to him); additionally they should be intelligent and outgoing. Michelle fits all of these qualities very well. So when I learned that they were dating, it wasn't that surprising. Of course we all had it out that he felt the need to hide something like that, but that was a minor detail. As for Michelle and I, though we were serious in high school, enough time has elapsed that I don't really recall those memories with any real clarity or emotional attachment. Now she is just a familiar face—almost like a friend of a friend. Or my brother's girlfriend. Which is what it has become. So Michelle and Nathan are now dating, somewhat seriously. She comes to family dinners and get togethers and has even been over when Cory and I have friends over for dinner.
The Rub: Cory does not like Michelle at all. She does not like that we dated. She thinks it is weird that Michelle and I dated for so long and is now dating my brother. She does not like her personality (Michelle is loud and boisterous, unlike pretty much all of my family, including Cory). I mean the list goes on and on. Another big one Cory hates is that I don't seem to mind Michelle. I know that she is a traveller and has had lots of unique experiences, so I ask her about them when she is around. Cory has accused me of flirting with her, of singling out Michelle in family conversations. "It's as if no one else is in the room when you two are talking." She would say. And, granted, we do have conversations in a group setting, but I don't consider them to be out of line and as I've said before: I harbor zero romantic lingering for Michelle.
So Cory and I are at a real point of contention. When I am organizing family get togethers, she is making it known that she does not want Michelle there. For anything. And look, I understand where she's coming from. I understand that even with a mountain of reassurance, Cory may never be comfortable around Michelle. I want to hold my wife's needs above all else, but I also love my family dynamic. I love the humor my brother and my wife and I share (or used to; he has since dampened that specific type of humor because it's probably a bit locker-roomy for Michelle). But this tension is palpable. it's driving a wedge between my brother and I because I have to side with my wife.
Anyway, I'm looking into a marriage therapist because Cory and I may have some uncovering to do yet. It may be that I'm not verbally encouraging her enough or that there is some house keeping that she and I need to do. But I'm worried that things will never reach that same level of unity that my family once had if Nathan and Michelle continue to get more serious. How can I better facilitate this? How can I be a better husband AND a better brother?
TL;DR: My brother is dating my highschool girlfriend. My family is close but my wife does not like my ex-girlfriend being included in our family get-togethers.


Source.

Man they need to make TV series outta some of these threads

This is what keeps Jerry Springer in business.

right?