AITAH for ending a long-term business partnership over repeated rudeness and unprofessional behaviour?

I (29F) run a marketing business with my husband (30M). A friend I helped in university, “Luke,” started a similar business a few months after me, and over the years we’ve helped each other a lot. During varsity I shared notes, textbooks, and projects with him, and later helped him when he got stuck with clients and business decisions. His wife “Emma” eventually joined his business (with no background in our field).

We specialise in websites, which they don’t offer, so they’ve referred website clients to us in exchange for an incentive per website. Because they needed websites themselves, we often allocated those incentives toward their own website and gave them very discounted rates. In total, their referrals equated to about half the value of the first website we built for them, but we still maintained the partnership in good faith.

Issues started last year when I referred my best friend’s family restaurant to them because their pricing suited small businesses better than ours. Months later, she came to me, uncomfortable after Emma made negative comments about me (saying I “love money” and don’t hire staff because of it). On top of that, the work quality from Luke and Emma and professionalism were poor, and communication became tense. The restaurant eventually gave them notice and asked me to help with the handover of assets, which I did for free just to help my friend.

After that, Emma’s tone towards both my friend and me became increasingly rude. The final incident happened recently when she messaged me late in the evening with no greeting, demanding a full spreadsheet of how much my business “owed” them, questioning past projects using incorrect figures, and insisting they should get monthly incentives for maintenance work (which was never part of our agreement). I explained that I track everything in our invoicing system and would respond the next day properly, as I was at a family dinner. Instead of waiting, she created a group chat with all of us and began sending aggressive messages, accusing us of not honouring agreements and demanding an urgent meeting.

Luke later apologised for her behaviour, but this wasn’t the first time I’d heard about her being rude to people. By that point, and after hearing about her speaking negatively about me behind my back, I felt professionally disrespected and personally uncomfortable. I told Luke I was still happy to honour our existing website agreement, but I no longer wanted to communicate directly with Emma due to her conduct.

He chose to end the partnership entirely, has since redirected several clients away from us, and we’ve even received a few suspicious negative reviews. I feel justified in setting boundaries, but also conflicted because it has affected our business relationship. AITAH for refusing to continue working with someone whose behaviour I found consistently rude and aggressive?