Should I be worried about my sister?

[Anonymous]

My sister is friends with my boyfriend and they are coworkers. When I ask my sister did she talk to him today she denies it but my boyfriend says they talked on the phone sometimes. For instance, i asked her if she talked to him a few days ago but she said no she didn't talk to him at all. My boyfriend said he did talk to her for almost about an hour and doesn't understand why she is denying speaking to him. I asked her yesterday did she speak to him and she said no but a few minutes later after i asked she called him. Yesterday, she called him while he was on the phone with me. He puts me on hold and he calls me back. When we get back on the phone he's okay but he suddenly begins to get really really mad seconds later. He then randomly tells me to stop sharing our relationship problems with my sister and to keep it between me and him. My sister doesn't share her relationship problems with me nor do i ever know who she dates because she keeps it private even though i tell her my issues only because she's friends with my boyfriend and she's had more relationships than i ever had so i come to her for advice. He knows my sister doesn't share her relationship details with me because i told him and he tells me not to share her any of our issues not just to her but to anyone.

[LazerBean]

Your sister kind of sounds like a skank, but I can't say for sure because I don't know her and I don't know how she was raised. I will say that someone who has been in a lot of failed relationships is not an ideal person to get relationship advice from, though, and that you should probably keep your relationship problems either to yourself. If you are really having problems, then pick one trusted person who has been happily married for a very long time (like 20 years) to seek advice from.

[Anonymous]

Seems odd for her to talk to him so much and deny it, probably has a crush on him