My girlfriend had implant out on 22/07/2013 and since then up to 11/08/2013 we was sleeping together almost everyday 2 times a day on occasions but then we split up and she slept with her ex from 13/08/2013 till 23/08/2013 but she said in that time she slept with him 3 times it's the 05/11/2013 now and she's 12 weeks pregnant what are the chances the baby is mine

There is no way to know what the chances are that this is your baby. You will only know once you have a DNA test done.