I don't think she is using me, I told her a lot of info she couldn't know as I have good relationship with former manager and know a lot of gossips, but she also provided some valuable information to me, so it's pretty mutual I would say. She is asking a lot of questions not only about work, but in general, it's like type of her communication. Like for example I was telling her about Christmas party and she asked if I finally got to know my new colleagues better, or we were discussing that she is planning to call somebody and the next day she asked "Do you know that I forget about it?", or I was showing her my new project and she asked "Wow it also have this functionality?". Basically 70% of her replies include questions like this, like she is trying to keep conversation going on, but she is also replying not really often so I am not sure about it.

One part of me is thinking the same way as you "It's not normal for a woman in a relationship to be meeting up with another guy for lunch and coffee" and other half of me is thinking that she probably goes to coffee also with other guy friends as she is working in a technical field filled with men, like maybe she believes in friendship between man and woman. But still, I would be not happy if I knew that my girl is going out to a coffee with former colleague. I also have this feeling that he probably does not know about our friendship or meetings at all, as she is responding to my messages 90% of time during worktime and 2 out of 3 of our meetings were during worktime too (she proposed lunch time, I was suggesting time just after work like the first time).

And there is this question that if she is really chatting with me secretly behind her boyfriend's back, does she want something more? She can always propose another coffee with me or start asking more deep questions, or start replying more often, or followed me on IG. At this point she could be pretty sure about me as I was always pretty enthusiastic about our meetings. Is she expecting from me to make first serious move? But I am not planning to do that cause she is in relationship and I know nothing about the state of her relationship, maybe if I knew that she is not happy, I would do some first move, but I don't know that (I basically know nothing about her relationship). And I would also make an *** of myself, as I am fundamentally opposed to harassment and recognise professional working relationships.

Thank you for your reply and sorry for another long post. I needed to discuss this topic with some strangers, because it really boggles my mind.