A father's heart

I was told by my ex-wife that my sons don't want to see me anymore. This is definitely not true. How can one's own son turn against the father? My ex-wife is a complete liar and an adulterous woman. She claims to be a Christian but this is nonsense. How can Christ ever advocate that a child be separated from his father? Her mother and father have similar deep seated issues that obviously need resolution but to be a liar and claim to be a God-fearing person is being silly.