Background: DH's little sister is about to break up with her boyfriend of a few years, but she is waiting until the end of the week so that she can finish her finals. She's waiting because they live together and she'll have to move out of their shared apartment back into her parents house. She's breaking up with him because they have been dating since a young age and they have both changed as people (although it's very obvious that boyfriend is still very much in love with her). At this point, little sister has told the family that she is breaking up with the boyfriend so everyone basically knows except for the boyfriend. I'm not happy that I was told, but I didn't say anything because it's not my business. My husbands family does not really like the boyfriend so they are all gung-ho for the breakup, particularly little sisters mother (MIL) who is very vocal in her dislike of boyfriend.
DH's has a best friend whom he has been friends with for many years going back to high school. Everyone loves him and he's considered a family friend as he comes over for family gatherings all the time.
Also, all parties involved in this soap opera are in their twenties.
The problem? Little sister confided to me that she and best friend have been texting each other for the past few weeks. Little sister went on to tell me that she confessed to best friend that she has a crush on him and apparently he told her the same thing. They've been texting each other continuously since then although she didn't tell me what the nature of the texts were. She also lives by where he works (retail of a sort) so she's been visiting him at work quite a lot.
I asked little sister if she had told the family about what had been happening with best friend and apparently her mother (my MIL) and sister (my other SIL) were extremely happy and can't wait for them to start dating. On top of that, little sister told me last night that her and best friend are pretty much dating except for the fact that she is still dating boyfriend. When she told me this last night I didn't trust myself to say anything polite to her so I just asked a bunch of questions and let her know that she is always welcome at our house.
To say that I am angry and disappointed would be an understatement. I told my husband about everything that had happened and what his little sister had said to me and he agreed that something needed to be done, but we don't know what.
Do we talk to friend, do we talk to little sister? Do we not say anything and let the chips fall where they will? We hang out with best friend all the time and have him over at our house quite a lot, but at this point I'm not ever sure I can be civil with him. What do we do?