My sister's Boyfriend is asking me out what do i do

My sister and her boyfriend have been dating for 3years now and 2days ago he started making some advances at me at first i wanted to tell my sister but i want her to be happy too so what do i do.

Here is my facebook address below help me please

I think she should know. If he's behaving inappropriately with you, then I doubt you're the last girl he'll do that with. It's just a matter of time before he cheats on her. It's better that she find out now, before she's wasted more time on him. Be prepared for the possibility that she might not believe you anyway. But you owe her the truth regardless. Good luck!

Only you know your sister. If you tell her without actually being able to show her any proof and she confronts him and he claims that you came on to him, who will she believe? If the answer is him, then I wouldn't say anything and I'd avoid contact with this guy unless, of course, he continues this behavior and starts getting aggressive with you. In that case, I'd record him or something so that you at least have proof. Even in that case, don't be surprised if she gets mad at you - at least until she realizes that she's better off without him.

Find proof first. Record the next time he approaches you or if you have text messages you can show her great. Dont tell her anything without proof coz it will just be your word against his and she wont know who or what to believe. You will hurt her far more if you put her in that confusing situation so make sure you have proof before you say a word

Keep us updated and good luck

I think you need to carefully tell your sister what he is doing. She needs to get out of the relationship FAST!