More potential red flags? Am I being unreasonable? I have no idea how to date.

So I (40M) was dating a 30(F) casually off and on since October of last year. I posted here a while ago about some potential red flags, and the general consensus was that I should probably run, not walk, away. Well, I gave her the benefit of the doubt and reached back out to her at the end of February and struck up light conversation which led into some casual dates, daily texting, dinner, going out with friends, etc. At the time, she told me she hadn’t even dated anyone since we parted ways in December, and honestly, I didn’t care if she had (in fact, I would have fully expected she had). Then it came to light she was actually seeing someone currently (which again, not an issue because I’m the one that reached out). However, the fact that she specifically misled me was a little off putting. She didn’t have to tell me she had been dating, but I think purposely misleading me wasn’t the best look. Anyways, she told me that regardless of my decision, she was ending things with him because she told him she wanted to see where things went with us. I thought that was fair, although I felt a little uncomfortable, because I didn’t want her ending things on account of me (I didn’t and don’t know the guy and I felt he deserved a fair chance with her).

Long story short (I think), a few days ago, I discovered (accidently when sending her money to cover dinner we ordered) that the guy she supposedly cut off has been sending her money for drinks when she goes out (including a night she was out with me). When I asked her about it, she brushed it off as him being desperate and that he sees her snaps when she’s out and sends money for she and her friends. She also admitted that they are back in contact texting, but he knew she was seeing me.

She claims she wants to keep seeing me, and that I never gave her a definitive answer on what we were, which that part is kind of true.

So, I’m contemplating ending things because my exwife of 16 years had an affair with a good friend for months behind my back and she knows that I have terrible trust issues. I felt like this behavior was a red flag, but does it sound more like an unfair response to “normal” behavior in the casual dating scene? I was with my ex wife since high school, so this was the first person I’ve dated in 23 years. I’m 40, and don’t have time for nonsense, but at the same time, I don’t want to ruin relationships because I’m misinterpreting things.

tl;dr;: Should I walk away from this someone who I think is being misleading at best, and deceptive at worst? Are these red flags or normal behaviors during dating in the early phases?