Hi vge..I am going through this also. I believed my h when he first started with the I don't love you when he said there was no one else. Only to find after he left that he had been texting and phoning a work colleague the whole time....one he is now living with. I too suspect that she had an agenda and was partly responsible for him leaving....but at the end of the day he is the one who ultimately abandoned his family. I range from crying and anger at the moment. At the moment I am in upset mode as he is now taking me to mediation regrading child access because I wouldn't let him have the kids on my weekend.
Unbelievable how he gets to carry on his new life yet he has such a sense of entitlement...me,me,me. Hope things start feeling better for you.