Boys and Girls . is this a good idea?

I have a gf rite now and we been going out for a month and half we made out and everythin .. my friend told me that he saw her with another boy and he describe the same place we been going to .. to make out I asked her if it is true and she said no and she was like ewww not that guy he is ugly and she sweared and she said who told u that .. so I went 2 my friend and he was like don't trust girls u idiot and he was like u should known her 2 years ago when she was a and most of ppl knows about her well I got in arugment with her and she did some stuff on fb long story and I told it I asked this question on yahoo answer got 14 answers and most of em saying I should dump her move on and she is I dumped her but she cried on the phone so I gave her a second chance... btw there is this one boy that most of girls love and stuff I think my girlfriend have a crush on him but if she dump me imma get so pissed u know .. I am not sure if she has a crush but seem like it should I tell my friend to come 2 my home and ask her out on facebook and see if she gunna say yes or she gunna say no cuz I have a bf should I tell him 2 come ... he will do it I know that he is like my best friend 4 long time do you guys think I should do this step or is it just stupid and can you explain 2 me why in details plzzz thank you! =)