Been lurking on TRP for a while under my main Reddit account and trying to learn as much as possible because I have been unforgivably beta my whole life (I am 32) and I can't deal with it anymore. I would have posted this on /r/relationships but I seriously doubt I would get any useful answers to my recurring problem.

Here is what basically happens: I end up building a good rapport with a girl I work closely with who I know up front has a boyfriend. We have good chemistry together and eventually she starts putting out IOIs and signals that I would definitely act on if she wasn't a coworker in a LTR. Eventually her attitude towards me ends up shifting dramatically and she acts towards me as if she was unattached and I had not acted on anything with her (i.e. she is turned off by me because she thinks I am a pussy for not making a move). Then she eventually cheats on her boyfriend with a different kid from work. This has happened on 2 different occasions and is really fucking with my head in a major way because it's not like I would handle these situations the same if the circumstances were different. My issue now is that I am in the middle of a similar situation above, although I handled it slightly differently this time. I was out w/ her getting drinks and walked with her to her car and tried to kiss her but ended up awkwardly kissing her on the cheek. Things were awkward for a couple weeks until the day before yesterday when I basically addressed what had happened the other night and told her that if I was out with her I was going to treat it as if she didn't have a boyfriend. She seemed to respond to it well, but then she came in yesterday and acted like she was completely repulsed by me (I had to engage all conversation, she wouldn't even look at me etc). It was soul-crushingly awkward all day yesterday and now today she is out of the office.

I know I made a ton of mistakes with this most recent girl and broke my "don't try anything with a coworker in a LTR" rule but I honestly couldn't deal with this turning out the same as the other two situations above and thought it would turn out differently if I acted differently. Instead it looks like it's on it's way to turning out the same way anyway.

My questions are basically: Has anyone else seen anything happen like this with a coworker and how were you able to avoid getting caught up in this type of thing? I know I fucked up by being too attentive/available to the first 2 (showing neediness and desperation) but those happened before I started lurking TRP and it really looked like this most recent girl was going to turn out differently until I fucked up somewhere.

Also, am I completely fucked with this most recent girl? I just don't want to deal with work being awkward and I thought being direct and honest about my intentions would be the best way to handle things so she doesn't look at me as her asexual work friend/emotional tampon. I am guessing I had at least one foot in the friend zone at this point especially after I tried to kiss her and ended up pussying out but part of me is wondering if her illogical (logic and reason lol) reaction to me being honest is just a massive shit test. At this point, all I really want with her is for work to not be awkward.

Thanks for reading, sorry for the huge, rambling post about how I know I need to stop being such a fucking Betamax and not shit where I eat.

TL;DR I don't act on signals/IOI's from female coworkers in LTRs because it's fucked up and also cuz I am a pussy, then their attitude toward me shifts and they end up cheating on their bf with some other guy at work. I keep getting in these situations and I fucking hate it.