Hnnnngh! - title edited to fit in Bloodline's ickle screen ;)

[Speelgoedmannetje]

metalman wrote:

the_leander wrote:
Problem is I'm not sure how many times I can continue to hear him call this guy daddy in front of me.

Your son spends almost all his time with your ex, the dominant parent. She's indoctrinating him because she wants to piss you off so much that you quit seeing your son. She has a new BF and wants you removed from the picture. Your son is only 4 and is not capable of understanding that he is being manipulated.

Divorce Poison: Protecting the Parent-Child Bond from a Vindictive Ex (Paperback)

Divorce Casualties: Protecting Your Children From Parental Alienation (Paperback)

I think this is the best advice; reading information of how others dealt with this.
I wish you best of luck, mate.