Search Results: flirting makes me uncomfortable

I see a lot of questions on here from guys and girls, saying that their partners are doing things that I would personally consider very inappropriate in a relationship. For instance, a mans wife is texting a male coworker non-stop and hanging out with him alone after work hours. Or a woman's husband is partying every weekend with the guys not coming home till 3AM every weekend. Or a man is still in contact and friends with women who he's had sexual relationships with. I understand there is trust in a relationship, but I also think that there should be boundaries in a relationship that we don't cross because it would make our partners feel uncomfortable. Also, if your partner is doing the above, then logically, there's a good chance that some infidelity is occurring or is about to occur. Maybe not always, but how are you going to ignore the possibility? These people seem to sit on this throne of "I trust them no matter what.", but that's honestly delusional thinking if your partner is doing these things in my opinion.

I believe the solution all resonates from reciprocity. Meaning, if I'm getting this girl snap-chatting me selfies of herself all day asking me things that imply she could be flirting, and I entertain that even though I know I'm not doing anything wrong myself, then it's still going to make my fiance feel uncomfortable. I ask myself, would I feel uncomfortable if a guy was doing this to her? If the answer is yes, then I won't put her in that situation. We're both pretty similar in our boundaries so it works out.

It's never been a "You can't do this.", because it never gets to the point. If my fiance was doing some sketchy shit that made me uncomfortable, and I told her it made me feel this way, and she kept doing it, then she doesn't really care about my feelings. If she doesn't care about my feelings, than it's time to end the relationship. The same works if she felt uncomfortable and I didn't do anything about it.

... Thoughts?