At a barbecue this past summer, my girlfriend’s so-called good-guy friend grabbed and groped her like she was his personal blow-up doll for 10 or 15 seconds, until I voiced my displeasure, and he stopped.    
      He then chose to ignore me and ask my girlfriend questions about me. How should I handle this jerk in the future? We’ll surely cross paths sometimes, and rational discussion is impossible with him.      
      P.S. The groping happened in front of the guy’s wife, daughters and grandchildren.
      - Beyond Annoyed

Since they’re supposedly “friends,” Girlfriend needs to confront Groper and tell him to keep his hands off. She should also say that his crude behaviour is especially disgusting in front of his family. If he can’t tolerate rational chat, she might ask herself, what’s the friendship based on?    
      If alcohol or drugs are involved in his actions, then a group of friends need to tell him that his habit’s destroying his close relationships, starting with her. She will NEVER allow his touching her again.    
      You and she should both keep a distance from him at future social functions. If he gropes again, he’s out of control. Be prepared to call the police and have him charged with molestation.

My boyfriend of nine months and I are co-workers who developed a strong and happy relationship. We spend a lot of time together with family and friends. He says he loves me no matter what, but sometimes makes reference to my weight.     
      He’s naturally thin and athletic; my family genes aren’t as fortunate. I’m only slightly overweight (15lbs.). In the past five years, I’ve lost almost 50 lbs. I'm still trying to eat healthy and work out often, but can’t lose weight as quickly as before.       
      He commends me for losing so much, but often says things like “I can’t wait till you’re skinny," or he'll make me feel guilty if I indulge in a small treat. I've told him that his comments make me feel bad about myself but he says he's just trying to help.       
      When he sees really skinny girls, he’ll mention how good they look and how good I'll look once I lose more weight. I feel like he’s comparing me to girls who have better bodies. When I bring it up, he gets defensive.      
      Am I just being too sensitive? He’s a great guy; I just don’t think he realizes how strongly his words affect me.
      - Frustrated

There’s a dynamic here that you need to turn around, so that this “great guy” doesn’t become your long-term critic. You’ve achieved a huge personal goal through your weight loss - which started long before your relationship – and you benefited both your health and your self-image. You did it for YOU, not for him.    
      He needs to appreciate that effort on its own and not take over “coaching” you into his image of what you should look like. Tell him this. And speak up clearly that he’s diminishing not only your own determination (part of what may have you reaching for comfort treats), but also the equality of your relationship. He’s not better/wiser/nicer than you, just thinner.    
      Also, stay in contact with your family doctor to assess your overall condition through further weight drops. Those “skinny girls” may be anorexic, and at risk for osteoporosis in later life. Make sure you stay at a healthy weight, physically and emotionally, eating a diet with enough calcium, vitamin D and proteins.

Is it wrong to ask your significant other to tell you where they’re going when she/he goes out with friends without you?  Or ask them who was there? Or, if they are replying/sending an email, text or phone call, to ask them to whom they’re talking? What is this behaviour a sign of?
      - Curious

I’m guessing you’re more than just curious, and your instinct is right if you feel this constant checking-up activity is over the top.
Whether it’s you or your partner who’s constantly on the other’s case, it’s a sure sign of a suspicious mind. IF there’s been cheating in the past, better to break up than waste all that energy on attempting control, without any trust.
If there hasn’t been any reason for all this hounding of the other person, then the behaviour is a blaring alarm of too much insecurity for the relationship to be happy.