TIFU letting my 3 year old watch Wizard Of Oz and potentially ending my marriage

A few years ago I thought it would be a good idea introducing my daughter to shows and movies I liked as a child. We settled for Wizard of Oz, innocent enough I thought at the time.

Anyway, she loved it. I know kids enjoy repetition and familiarity so it has been left on the tv a few times since while she played and I cleaned up (mother of the year, nice to meet you).

Anyway, a few days later I left her at my mother-in-laws for a few hours. Later that day when I go to pick her up, I am met with frosty attitudes. Normally I sit and chat with them, but they were rather awkward and feeling the tension I thought it would be better to leave, thinking I had walked in mid-arguement.

Nope.

When my husband came home that day he carried the same attitude. Now I was beginning to think I had done something to offend his parents but each time I asked him what was up, he would bluntly respond with "nothing". I knew something was up, but he couldn't bring himself to say it.

Fast forward, out of the blue my husband confronts me with "who's Richard?" Confused I was like, who? He continues to confess that our three year old daughter told her grandparents that she loves Richard, that "mummy loves him too" and is really looking forward to seeing him again.

At this stage, I am STUMPED. Who do I know called Richard? He gets visibly aggitated the longer he explains, asking again who he is and when has met our child, that I have no right to do that, demanding to know how long the affair is going on for. At this stage I am white, I am so confused. I continue to explain I GENUINELY have no idea who he is or where our daughter got this idea from.

I call our daughter into the room, maybe she can enlighten us? So little Miss Innocent waltzes in, oblivious to the very heated discussion we were just having.

I kneel down and ask "Sweetie, who is Richard? You told grandma all about him", and she responds "the green man mummy, the one with the fluffy hat" singing "We're off to see Richaaaarrrrrd, da wonderful Richard da wazzz".

FFS.

Once we had that cleared up, a few belly laughs later we had to explain to his parents that our daughter is not a little snitch.

TL;DR My daughter got a name wrong in her new favourite movie, in-laws thought I was having an affair.

Edit: Didn't expect this to blow up and have people investigate my past. Marriage ended a few years later, not related to this incident and irrelevant to the original fuck up hence why it was left out.