Definition: Given a real-life anecdote of a complex ethical situation, generate a suitable title that describes the main event/root cause of the situation. Imagine that the given text is a social media post, and you have to write the title of the post, so the users can decide to read the main text or not.
Input: Some background on their relationship.  SIL and her fiance have been together a little under a year now.  Only about 6-7 months if you exclude all the time they have been broken up (on 3 separate occasions).  Reasons for breakups.

1.  He wasn't "motivated enough" she said because he worked part time and used public transport.  He got a better paying job that he hates so he could afford a car to impress her.

2.  She "needed to be free" which was code for "I want to take a trip to my old home town and sleep with some guys I had a thing for back in high school."  After a few days back home at different men's homes she came back and immediately got back together with fiance.

3.  This time she broke up because she thought she had a chance with her boss.  He turned her down and she took fiance back *again.*  Total breakup time was about 12 hours.

Well the last breakup happened a couple weeks ago and just the other day fiance (who I'm convinced doesn't actually have a spine or any sense of self worth) proposed to SIL just 2 days after she complained to him in front of the entire family that she has been waiting for him to propose.  When my wife told me about it I shrugged and said "cool."  Wife is more sick of her shit than I am having grown up with her so she and I were both pretty "meh" about it.

Well we were just over at my MIL and FIL's for dinner with SIL, fiance, wife and I.  SIL was showing off her ring and I said "it looks nice."  Everything seemed fine, but a few hours later FIL and MIL came up to me and told me how I need to be more enthusiastic and supportive of the engagement.  I told them that I won't be a jerk to her, but we all have seen how the relationship has played out.  It has been a dumpster fire.  I was told my comment was out of line, and my wife agrees.  She thinks I am not wrong to not be as enthusiastic as her parents want though.

Am I the asshole for being lukewarm on this whole thing?  She treats him like shit and he takes it.  Fine his choice, but I don't feel like I have to be enthusiastically congratulating her on an engagement when I honestly think it is going to end either before they even get married or shortly after when she gets bored and starts cheating on him now that she can't just make short temporary break ups to clear her conscience when she wants to sleep with other men. 

not pretending to be happy for my SIL getting engaged when we all know her relationship is a dumpster fire