When we started dating, my boyfriend said any demand to drop his female best-friend was a "deal-breaker." Her ex (his friend, too) had cheated on her; my boyfriend spent time comforting her.
      She "came on” to him. It cost the men’s friendship; the couple divorced. She wanted to marry him, he declined, she soon married someone else. Meanwhile, their children got close, and they spent more time together after his second marriage ended.
      Whenever his friend fights with her husband, she heads for my fiance's apartment. When I saw them together socially, I felt ignored and saw her attraction to him. We’ve been arguing over this one issue since January! My concern was the depth of their emotional intimacy.
      Finally, I overheard her asking, “Are you really, really busy (Friday night)?" I’d always respected his Friday nights “alone time” with his child. I broke up. After fighting so hard to keep his relationship with her, he let me walk. Should I have ended it much earlier? Or, did my own fears and jealousy create this break-up?
      - Busted-Up

You hung on too long, while they continued their emotional affair. Despite his having a close female friend, you had to become primary as his full-time partner. The boundaries between couple closeness and friendship should’ve been made clear … by him, not you.
      It’s likely his two previous marriages and other relationships were affected by his “triangle” approach: It’s a way of never becoming too enmeshed in a spousal connection. By hanging onto her instead, he’s always got an out, or at least an emotional barrier from the person who’s entitled to want more.
      Your “fears and jealousy” blocked your common sense, which could’ve seen sooner that his deal was a set-up for eventual failure.

My wife of 12 years is a wonderful woman and awesome mom to our kids. However, our sex life is pathetic - boring, quick, unsatisfying - and I’m not sexually attracted to her so have difficulty initiating. She has many sexual inhibitions and hang-ups. During a low time in our marriage, I was caught in an affair, now over.
      With counselling, we came out stronger and happier as a couple, but I'm having a hard time letting go of memories of the intimacy that we shared and that I long for. I feel I’ll never have that feeling with my wife, but I should stay in the marriage for the family’s sake.
      I’d feel guilty destroying my kids' lives for the pursuit of better sex, yet feel I’ll leave when the kids are older.
      - Conflicted

You’ve already got an imaginary foot out the door; if you think your kids won’t eventually sense this and experience emotional effects, you’re wrong. You and your wife need more professional help, with what’s fuelling this ongoing problem.
      She needs to recognize that it’s not just about you cheating, but about her disinterest in sex … each issue feeding the other. And, if you’re not attracted to her for other reasons - whatever they are - she deserves to know what she can consider working on IF she chooses, and what’s at stake.
      Remember this: Intimacy comes easily in an affair - there are no responsibilities together, no hidden power struggles, no time demands of household chores and kids. Couples have to create and maintain that kind of time and space for their sex life, especially when it’s not going well.
      If you leave without having tried every approach possible, you may still feel guilty.

I'm 52 and lost my husband three years ago. I miss him terribly. During his sudden illness, I couldn’t eat and lost a lot of weight - but I’d gained a lot in previous years. I'm tired of people (well-meaning) asking how much I've lost. I feel it’s basically the same as asking, "how much did you weigh before?"  
      My doctor has pronounced me healthy, and not underweight.  How do I politely say, “None of your business”?
      - Weighty Annoyance

Be proud of your healthy slim looks! Since most people are well-meaning, they’re NOT looking for a former fat count; your annoyance is part of your grieving, since it reminds you of the tough time you experienced.
      Try a response like this: “I’m healthy, and that’s all that counts, now.” Then change the topic. If anyone persists, say quietly, “I miss my husband, not the weight.” If necessary, walk away.