Am I overthinking this, or are these blurred boundaries with my 32M girlfriend’s 32F golf instructor?

Hey everyone, looking for some outside perspective because I’m trying to approach this rationally and not let past baggage dictate my reactions.

My girlfriend (32) and I (32M) have been together for about three months. Overall, things are going really well, strong connection, good communication, no major issues so far. This is the first situation where I’ve felt genuinely conflicted.

She’s been taking private golf lessons with an instructor who’s over 60 for around 2 months. After every lesson, they go out for coffee together. On top of that, he sends her songs on WhatsApp, as it referenced about her which already feels a bit unusual to me.

Recently, she also invited him to her office where she works, it’s a pretty fancy office just to show him around.

Another thing that made me pause: I gave his contact to a friend who reached out asking about golf lessons, and he said he has no availability on weekends. Yet he always seems to have time to get coffee with my girlfriend after her sessions.

What complicates this for me is that while I genuinely trust my girlfriend and don’t think she has bad intentions, there’s also a part of me that wonders if she might be a bit naive about the situation. This is a man in his 60s, communicating frequently with a young, attractive woman half his age, and some of the interactions don’t feel purely professional anymore.

I don’t want to sound like I’m blaming her she’s been trustworthy so far, but I also wonder: should someone in their 30s know better about potential boundary issues like this? Or is it reasonable that she might see it as harmless and not think twice about it?

I also want to be transparent that I’ve had a bad experience in the past where I trusted someone completely, and it turned out they were involved with an older man in a way that was much more inappropriate than I realized at the time. Because of that, I’m aware I might be more sensitive to situations like this.

I’m not trying to control who she sees or accuse her of anything. I just don’t know how to balance being trusting with not ignoring something that genuinely doesn’t sit right with me.

So I’m looking for advice on: Is this kind of dynamic normal for a coach, student relationship?

How would you approach a conversation about this without sounding controlling or suspicious?

How do you tell the difference between valid intuition and projecting past trauma?

Any honest perspectives would be appreciated. Thanks for reading.