My meta confuses me

My BF (James) practices solo poly. We are both in a relationship for more than a year and he sees other people casually. He had a childhood friend who was kind of FWB. This was also someone who he had dated in his high school and broke up because they had to move away for college. He was in a monogamous relationship with her at that time.

Few years later, they met again and started dating. James was poly now and had told her upfront about it and told her he is not interested in a monogamous relationship. She wasn't sure if she could accept it but was willing to try it for him. It didn't work out for them and they had a very amicable breakup and up until 6 months ago, they still met and hooked up anytime he went to his town to meet his parents (about 5 hours travel from where we live).

Background information: James' parents are poly and have been poly their whole lives. They are not married and James doesn't believe in marriage.

Now his friend got a job in our city and moved here 2 months ago. When they decided to get together, he had told her about our relationship and she was okay with that. James and I usually have 2 nights a week and if his and my schedule allows an occasional lunch or an weekend at my home with husband and kids. Last month my husband had to leave the country for a project and I was literally a single mom running like headless chicken trying to do everything.

During this time, I was unable to meet James for more than a lunch or something and he was very understanding and even offered to watch the kids if I wanted to just rest and sometimes we just hang out at my home but it was significantly less than what we usually do. James started hanging with his friend more during this time and they made plans to go away the memorial day weekend. All was well until the day before they left, I slipped on some juice and had a severe ankle sprain, thank god not broken.

James offered to cancel the trip but since my MIL stayed with me to help, I told him to go as planned. I knew I looked a picture when he left, crutches, ankle bruised and swollen and I was in pain. The first day, he frequently checked in and asked how I was doing. Pain medications always make me a bit loopy and my answers were a bit slurry but by second day the pain started to improve and I started to feel better. I never asked James to cut his trip short but he stated he couldn't enjoy the trip and it wasn't fair to his friend either that his mind wasn't in on it.

After my husband came back, things settled down to relatively normal and James and I had to reschedule our date a couple of times because husband was still suffering from the time difference. I always double checked with James before re-scheduling if he is okay with it, hell 1 night he came home and was playing cards with my husband even long after I went to sleep. I honestly didn't think anything was wrong until my meta sent me an email blaming me for James canceling the trip with her, he cancelled a date with her because I wanted to see him that night and how much he and I message each other. I will admit the last one. Unless he is on a date or with other partners, I usually text him at random times and we both have a habit of sending cat pics or vids anytime we come across it. I have never interrupted their date and James sensitive to his partner's feelings will never text during a date. This email came out of nowhere for me. I have never even talked to this girl considering she was only here a month.

How do I proceed now? Do I tell James of the email? Do I meet her and explain what happened was not with malicious intent? Husband thinks I should just show the mail to James and let him decide the course of action.