He’s a father figure to his ex’s kid

Last day for Bruins help. I like their facial expressions in this one.

I have been with the same guy for two years now and we are engaged. We love each other very much and he has been my rock through a lot of difficult situations.

My problem isn't exactly a problem ... it's a child.

Before we were together, his ex got pregnant from another man while still with him. Being the great guy that he is, he decided to be the father figure to the child despite finding out that the kid isn't his (she isn't sure of who the real father is). At first I was fine with it -- she lived in the same town and we saw him often. I'm not a mean soon-to-be step-mother like in the movies -- I really enjoy the time I get to spend with him and his father.

Then the ex decided to move in with another man ... about three hours away. So he has to drive to get his toddler "son" six hours away every three weeks and then bring him home (because she doesn't drive). He also has no legal rights being the non-biological father.
I love them both very much but I have no grounds to talk to the mother and be like "you need to get your act together?" What do I do?

– Confused About Kids, Worcester

You went into this relationship knowing that your boyfriend considered himself a father to this kid. That means that there's very little you can do. You can talk to your fiancé about getting some legal advice -- perhaps he has more rights than he thinks he does -- but that's about it for now. When the kid is a bit older, he can hop on a train for visits. You just have to wait it out.

Please do your best to preserve your relationship with your fiancé by making peace with the fact that his ex is always going to be in your life, ticking you off. If you expect it, it'll be less annoying. Because ... the kid isn't a "son." You have to delete those quotes and approach this like any other step-mom.
Also talk to your fiancé about how he can plan for the future. Has he talked to his ex about how this will work in a few years? Does he know whether this new guy will play a real role in the kid's life? Help your partner get some answers so you feel less helpless in the relationship. That's the best you can do.

Readers? Anything she can do? She's asking about how to deal with the ex, but how can she preserve her relationship? Discuss.
– Meredith