what was my fault???

i have loved my gal a lot...still im loving her tooooo.....she is the only life for me....i want spend my restlife with her...i see her equal to my mum....truely i loved her lot...but she have cheatd me....she loving the another one....i asked her y u r done this...y u r cheated me???? she told me "no one is perfect in this world..so mind ur own busineess"...after tat also i dont get any anger on her...becz im loving her that muchhh.....i love u dr.....still im loving her.....wat was my fault?????? :( ;(