Now I'm in trouble with both of them...ugh...?

I know the feeling! Believe me! They want you to have a good relationship with their family but yet whatever you say is wrong! LOL. You aren't wrong...you handled it perfect. I guess next time, you're going to have to even leave out the "I'm sure it's okay but..." and go with a flat, "I'll check with him and have HIM call you back." Because being polite gets us all in trouble. Happy Easter anyhow!