Need advice on female colleague

Over this year I’ve become really good friends with a woman at work (I’m male). She is a couple of years older (we’re early 30s), she is divorced with a young child and I am in a LTR with my girlfriend who I live with. Me and this woman have grown quite close - we have lots of mutual hobbies and interests and when we’re together we just “click”. Our senses of humour are the same and we spend our days sharing jokes and chat. We text daily - long back and forth conversations. She is very attractive - looks and body. She works out a lot (one of our common interests) and I’ve always told her I’d love to see her body given the exercise she does. She just laughs it off. I admit I love flirting with her - and she does flirt back but I have been shut down a couple of times / she’ll ignore certain questions. She has even met my gf so knows she exists. The other week things got a bit “hotter” after she told me she was drunk and the next day woke up with her clothes on the stairs and no pjs on. I jokingly thanked her for her drunk photos and said she had lovely lingerie (this was all in jest). She laughed and said no she wouldn’t do that. I asked her what would it take to see her body / sexy undies and she replied if we are ever both available she’s consider it. I replied that I wasn’t availabile and wasn’t going to be, what a shame etc. No response from her. I text the day about something completely different thanking her for something she’d offered earlier in the week. Again, no reply (but I didn’t ask a question). So the next day I text again asking about a work call and made a few jokes, called her beloved etc to try and test the waters. I got a one line “too busy” curt reply, I replied saying oh no that’s a shame hope things quiet down for you soon. That was five days ago and she’s left me on unread. Is this friendship over? I was clear I had a gf? Should I leave things as they are or try and smooth them over?
Can I just add that a couple of colleagues mentioned our “obvious chemistry” and “romance on the cards” recently. We both laughed it off. We occasionally meet for a walk during work as we live close by and nothing has ever happened. I’ve suggested coffee / lunch / invite to my house but she hasn’t said yes yet, other than in group things. I do think we like each other but she’s conscious of my gf.