"You're not his mother"

So, I'm the wicked witch. Devin's mother is mad at me because I'm spending time with her son. She claims that one night when she called and asked what he was doing he said, "I'm watching tv with my mom and dad." Chase and/or I are always in the room when he is on the phone and neither one of us remembers this. She also threw out that on another occasion she called and he didn't want to talk because he was "playing a game with Melissa". This is true.

She yells at Chase's Mom that "Melissa isn't his mother" and that isn't my intention. Devin has a mother and I'm not trying to replace her whatsoever. I feel as though I'm damned if I do and damned if I don't. If I am mean to Devin I'll get chewed out. If I'm nice to Devin I am accused of trying to be his mother. We live in the same house, am I not supposed to show Devin any kind of attention? Ignore him when he walks in the room? Choose to play with only Garrett and Jacob and not include Devin?

I don't get it.