Absolutely right ! The goal should be to support the relationship and advise should be taken from those who don't have some personal issue going on as well , because that person will reflect his own situation onto yours.

Me being in this perticular spot right now, I'll let you know that , i don't think a best mate will take just your side until he is just your mate and doesn't even know your partner.

My best mate is having issues right now , and he vents and removes his frustration while we go for a drink or match. I give me a reality check because I know his girl too. ( He had introduced her to me while we went on trip together ) , When he understands that sometimes just the situations are in certain conditions which seems bad and it's not her fault , i can see his wheels turning and we go get flowers so that he can apologise and make things right. It's good to talk to others but make sure if it's your best mate then he should also know her .