Great you’re concerned. She may not “open up” isn’t compelled to,May not feel able to
keep a watchful eye on her. Given your military past you’ll know what fear,reticence , avoidant, look like and be tactful in your interaction
I note She hasn’t disclosed any contact details to you, that’s unusual in a tutor
To retain the engagement be consistent in your behaviour, no intrusive or unusual questions and just keep a wee eye on her

Is her reluctance just that she would like privacy? I may be misunderstanding but is it not normal that she may want boundaries with someone she is teaching?

From what you've written I would be sharing the same concerns as you.
Is she still working for the charity you spoke of? There should be either a manager or supervisor there who will take any suggestions of abuse seriously. Certainly this was the case with charities I've worked in previously. We took any concerns like yours seriously and were able to find support etc for any volunteers experiencing abuse etc.
I would suggest you contact the charity where she works (ideally at the location she works if possible i.e. the shop she works in if she's a shop volunteer) and just share with them what you've said here.
I really hope she is able to access the support she needs and I also want to say to you OP well done for noticing and for handling your concerns with her so gently and respectfully.

Does she have your contact info?

I'd for now focus on her knowing you are a safe place and person who she can call any time. Are the lessons at your home?

Depending on where/what the organisation is like she volunteers with you could approach them but this may be risky! Either in terms of putting her at risk, or her closing off both with her volunteer role and with you. Approaching the charity would be very dependant on who would deal with this and how they'd do so Imo.

There may be some element of over thinking. You seem very fond of her given she's your piano tutor (not your employee).

There could be many underlying causes of anxiety for her in a same sex relationship.

She may suffer from other mental well-being difficulties.

Her relationship may be breaking down.

There are many reasons as to why she doesn't want to discuss with you.

I don't think questioning her or trying to get her to open up is going to be helpful. Just listen when she does want to talk, and if there is something going on, sign post her to professional help - womens aid, freedom programme etc.

I can understand you being cautious of involving too many people.
At the same time, if she is in fact being abused then holding off maybe isn't the best strategy either. It is a really hard situation for you I do appreciate that.
Maybe mention to the manager that she's been looking drawn/unwell lately and they can keep an eye on her from that perspective at least? Just a thought.

I'm going to be frank. Your post sounds very weirdly written and gives me the creeps. Why the hell would an abused person confide in someone they are giving piano lessons to?

You could be overstepping the mark as much as you could be right

Other than somehow letting her know she can talk to you leave it, you are coming across a little intense

A possible explanation is that she is claiming benefits and working on the side? You don't really have any evidence of abuse, and even if you did I'm not sure you are in a position to help other than by being a general listening ear and building up her confidence.

It's beyond weird that you call her your employee. Honestly, it stands out a mile and gives me the creeps

have you got specific experience of helping people in an abusive relationship? if so, can you include that in a conversation. So rather than saying 'come to me if you want help', you describe a past situation where you helped person A move away from person B who was abusing her. That gives her the information that (a) you know how to help and (b) that the behaviour of B counts as abuse and would be taken seriously.

after that, drop the subject. you will have shown that your door is open and you have to leave it to her to decide what to do with the info.

You seem over-invested This is not a child and not your employee. I can't believe you are dreaming up all this weird stuff and considering sharing it with third parties including her employer! I would be beyond livid if i was her

First post after years of lurking, but this post stood out to me as I've heard of co-workers like you saving lives and securing convictions.

This is extremely disturbing, but please watch it. This woman's manager documented the abuse and probably saved her.

I was this woman a long time ago. Thankfully, those days are far behind me now.

If I'd found out that someone that I did some casual work for had been chatting to my boss about my mental health without my consent and was planning on sharing their concerns about me, it would have had the opposite effect that you are hoping for. I wouldn't have opened up, I would either have run in the opposite direction and quit my job or told you to f-off, and probably still quit my job.

My job was the one thing in my life that was stable, and for a while the only thing I really had any control over. Acquaintances interfering in that, however well intentioned, would not have helped. Nor would secret notes and hand squeezing.

Just maintain a polite and friendly working relationship with her. You may be a million miles off in your assessment of the situation, and she may not need "saving" at this time. There may be a good reason who she keeps a distance from former friends and family members.

Can I ask if you’re male or female?

Women often find it uncomfortable to eg give men contact details or discuss single sex relationships with them because of the way that men often behave in those scenarios.

That would be no reflection on you - just her own personal experience

Thank you for your honest reflections OP. I do wonder if you are overly invested in her? you talk of her ‘gorgeous laugh’ etc. it seems more of an attachment from your side than a normal teacher boundary. Also the use of employee when she is your teacher from my understanding? It’s fine to say you’re ‘always here if she needs help’ but don’t pry further. It could push her away. Could the army part of your career make you more want to help potentially vulnerable people?

I don’t have any advice for you OP, but you seem in a MN way to have found some of those people who seem to get a kick of of telling anyone that they are wrong, often to escalate into being ‘ creepy’ etc.

FWIW, I had a similar situation with someone who gave me private language lessons, although I went to their quite isolated house for them. She was very thin, quite closed up, nervous, and had an unusually disconnected and isolated life for someone of her age and ability.

as this was a semi rural community, I asked a couple of people ( WI) who had lived in her road before they moved to the more remote cottage about her. There was some general unease about her husband, ‘he seemed very controlling’.

There wasn’t much we felt we could do ( I shared these lessons with DH who was also uneasy). In the end I just told her that if she was ever in the village and fancied a chat, she would be welcome. I just wanted to give her a hint of an open door.

It is odd that she has moved to London, but has no family or friends there. Is she British? Maybe she has visa issues and can’t get a bank account? A lack of bank account means no job.

Also, she’s isn’t your employee. She is a freelance piano tutor. She could be ill (physically and/or mentally) and not abused. Don’t ask her too many personal questions. Talk about other things so over time she feels she can trust you if she needs to talk.

I would not contact her boss it’s intrusive she’s not asked for that
its ok to be concerned it’s not ok to stage an intervention
potentially you compromise her if you disclose concern

Yes the writing sounds like bad saviour porn to be blunt.

Why do upu think your teacher is your employee?