In a Hetero relationship and meeting up with a lesbian “old flame”?

7 years ago I fell for an older lesbian... I ended up going overseas for a year before I acted on anything. We kept in touch intensely for the year I was gone however when I came back, completely ready to jump right into it, I found she had been seeing other women. I got a little possessive (I was young and immature. 8 years difference between us) and long story short she cut me off. We fell out of touch for a while, and I ended up happily in a long term relationship with a man. I’ll be in her city in a few months and I messaged her. To my surprise she was super keen to catch up and organised time off work and everything. I’m not sure yet if I will go to her place or we will meet out. What should I do? I still have such strong feelings for her that have been stirred up again. I also haven’t told my boyfriend and don’t plan to.. I gave him a watered down version that I was once really attracted to a woman but it didn’t go anywhere. How should I be around her?? Is this a mistake?