3 Year Old said he's scared to go back to his Mother's house.

Background: Ex and I had 2 kids (now 6 and 3) and we split up just after the youngest's 1st birthday, so he doesn't really remember me living with him full time.We both have new partners; Ex lives with her new boyfriend and Mother, I live with my fiance and my parents while we save. The kids are with her Sunday night to Friday night and we have them Friday night to Sunday night.Now my 3 year old's vocabulary has exploded over the past 3 months but he still has trouble enunciated some words.Story: So for the past few months, at least 90% of the time my youngest will say that he doesn't want to go back to "Nanna's House" and that he wants to stay at Daddy's.Tonight though, he said that he didn't want to go to Nanna's House because he's scared. My fiance and I kept asking why but he couldn't say what he was scared about clearly enough to understand, then he started getting shy because he had to repeat himself a few times.We're thinking next Friday night we're going to pull my 6 year old aside and ask her why she thinks her brother said he's scared, but she's also been caught out telling lies recently so we'll be careful with what she says.Any advice on what other steps to take? Should we leave it be for a bit or should we go speak to a GP about what to do next? via /r/Parenting https://ift.tt/2xNIqag