DH,
At the risk of sounding unsupportive, I'm going to ask a few questions and offer some insight into what your wife may be feeling. Please understand that I KNOW the logic and "non" thought processes I apply to the situation may be totally off from what your wife is thinking. I also don't condone the way she handled the situation or fault you for your response.
Questions:
Do you think your wife saw your son's lack of interest in his sister's performance as invalidating to your daughter?
Do you think your daughter was in any way disappointed not to see you and her brother in the audience?
Do you regularly give your children the option to not attend the performances/events of the other?
What is the general expectation for how your wife is treated on Mother's Day?
Were you a bit relieved to be able to sit away from your wife and play on your phone during the concert?
Depending on your answers, in my "non" world, I think I would be fairly pissed at you myself.
In my family, my children are expected to support and celebrate each other's talents and skills. Even when S14 would rather not be at his own performance, S18 is expected to be there unless he has a very good reason. I'm a bit more lax about what the expectations are for their level of engagement while in the performance. I am okay with a bit of gaming or surfing on phone or tablet during an auditory performance (as long as it's not distracting to those around us) and at sporting events when their brother is not on the field or the game is rather slow.
As a daughter, I place a LOT (too much) emphasis on my dad's approval. Your daughter may be more secure in your approval and pride, but if I had a daughter I would be hypersensitive to my husband's level of engagement with her. Even now, with my boys, I find irrational levels of hurt and anger triggered when I feel like my husband is "abandoning" my boys the way I feel I was "abandoned" by my dad.
As a mother (and a pretty darn good one), I expect to be queen for the day on Mother's Day. Not that my family agrees with that expectation.

. Usually, I still tend to pick the foods I know my kids like and do the things I know they will enjoy. Last night I actually chose food from a place that is not S14s favorite, but he lived (scarfed down everything he ordered, like a good teenager) and we had a good time. Even if I don't express it, I do feel fairly slighted when things don't go "my way" on Mother's Day. It's supposed to be the one day of the year when I chose whether to put my feelings aside or not. The other 364 days of the year I generally do, so it doesn't seem like too much to ask.
Now we start getting into the muddy waters of marital dynamics and expectations. IF you had any sense of relief in having an excuse not to sit with your wife, you had better believe she sensed that and was hurt by it. As a "non", I have to admit that, even if I felt equally relieved to not have to sit next to my husband, I would feel hurt and would focus on the idea that HE was the one who got to escape while I had to be the responsible one and sit dutifully and attentively through the performance. (I wouldn't have spent it text bombing, but I would have been seething). I also might have focused on the fact that, by virtue of you having been gone having a grand old time in Asia, I have been the one stuck with all the discipline and the ONE thing I ask you to do ON MOTHER'S DAY (get your son to sit and watch his sister) you shirk.
Now, lest you think that I am actually your wife taking over BeagleGirl's computer... .
Even if some of your wife's feelings are understandable by a "non" wife, I suspect that her response is fully BPD. As a "non", I would want to express my hurt and have it validated (probably true of your wife as well), AND I would want to understand what was going on in my husband's mind that differed from the hurtful intentions I have assigned to him (probably not something your wife is capable of wanting/comprehending). I would want to come to an understanding of what we should both strive for in the future based on our new insight into each other's thoughts and feelings.
Some things I think you probably want her to understand:
Your thought process is still a bit foggy from jet lag, so communication from her needs to be clearer than usual to avoid misunderstanding.
Your feelings and subsequent actions are being impacted by the current stress in the marriage and you are unsure of how valid those feelings and actions would be outside of the current context. You're trying to sort that out, but don't always have time to do so before action is "required", so sometimes you get it wrong.
You did what you believed she wanted you to do and didn't really think about whether it was the best thing to do. (see the previous two points for why you didn't fully think through it)
You did not intentionally ignore her texts and would like her to take some time to pull out the anger caused by her belief that you did and put it aside so you are just deal with the things you actually did.
The constant communication/escalation in communication of her anger makes it hard for you to not shut down emotionally.
You want to have some confidence that the two of you are "playing by the same rules" and working towards the same goals.
Please feel free to add more to the list of "things I wish my wife would understand". I hope that it will help you sort out your needs/desires, even if you don't have reasonable expectations that your wife actually will understand those things.
BG