Dear Amy: I have a 4-year-old son. His mother and I have lived apart for the last 18 months. He spends time equally between the two of us.

For the past few months, he has demonstrated a strong preference for me over his mother. For example, at times when I drop him off at their home he throws a huge fit, wanting to come home with me. He has also begun saying that he doesn't love his mom -- he only loves Dad. He has even thrown a fit when she picks him up from day care, saying he wants Dad to pick him up or that he wants to go to Daddy's house.

I have tried talking to him, but it's not easy to explain that he can love both Mom and Dad when he's so young. I never speak ill of her to him, and I even tell him how much Mommy loves him, but his response is always, "I love Dad."

I don't think I am doing anything to promote his behavior. Any ideas on what would cause him to act/think this way -- or how I can alter it? I know it's upsetting for his mom to hear this and I hoped maybe it was just a phase, but it seems that it's progressing.

-- Concerned Dad

Dear Dad: Let's stipulate that there are no serious issues in the mother's home.

If that is true, then I would say that yes, you might be unwittingly promoting this behavior when you respond to a tantrum by talking with him about whom he loves.

It's possible that this is not about his mom. He might be working extra hard to ingratiate himself to you because he's afraid you'll drift away. He needs to know that you are always going to be right where he left you. Reassure him.

The way to help him make transitions is to give him the most stable, predictable and calm environment and to encourage him to try to behave appropriately.

You and his mother should develop a strategy for dealing with this consistently. Make sure there isn't anything going on at her house to make him anxious.

When he freaks out, calmly comfort and reassure him: "Buddy, you're going to be fine. I've got to go, but I'll see you tomorrow. Let's go over here and say a nice hello to Mommy and I'll see you later."

Dear Amy: I share the "Office Grouch's" feelings toward birthdays being celebrated at work.

Birthdays are important when we are kids and then occasionally after that. But not everybody celebrates aging, and I don't like to be asked to contribute money for someone I might not even know. I'm glad you weren't mean to this poor grouch when he confessed how much he hates these celebrations.

-- Happy Reader

Dear Reader: The real "celebration" these office birthdays offer is an occasional break from work!