Hey guys. I really doubt there's much I can do in this situation, but I'd still like to here what others think, even if it's only advice on how to cope with it.

So here's the backstory: Few years ago, I dated this girl for 3-4 months. Things went sour and we broke up. She instantly got back with her ex-boyfriend (part of what was making things go sour).

Few months later she says she's pregnant with my child. At this point, I don't know what to think. She's been dating her ex for months now, so I have no clue if this child is mine. I dropped the ball and panicked. I didn't know what to do, so I just waited.

A few weeks after the child was born, I said I wanted a paternity test done and it turned out that it was my son. I did what I knew was right and stepped up to take responsibility helping her with cash when she needed it. She still lived with her ex for a year or so.

So now it's 2.5 years later. I see my son 3-4 days a week and I've been paying a buttload of child support for around a year. I've known that my son's mother still let's her ex see him, but I recently found out that he's been calling him daddy, just like he calls me. I confronted my son's mother, and she said that it's my fault because her ex was there for her and the baby throughout the pregnancy and a year afterwards. I explained that I had a test done right away, and she continued living with her ex, which I had no say over.

So here's where my questions come in: I believe that she can let her ex see/watch my son, but I have a problem with him continuing to play daddy with my son. I'm pretty sure he tells other people that it's his son, and obviously he tells my son that too. Is there anything I can do to stop this?

I'm comfortable with the fact that I'm a good father, and I know my son sees that, but it crushes me to know he's calling someone else daddy. It also crushes me that this guy is playing father while I'm the one busting my ass with child support and the court system to see my son.

Sorry for the wall of text. Maybe this is just a good way for me to vent my frustrations. Thanks for listening.

Edit: Since it came up in a comment... The ex does not live with my son's mother anymore. They're not dating. She lets him watch and see my son.