Feeling off about NP's behavior with new fwb.
I'm getting some ick from my NPs new relationship and I really need some perspective. Sorry it's gonna be long.
TLDR: my partner is having some issues being totally honest around his new fwb, who is a coworker, when it's never been an issue with others, and it's making me question whether I can trust him.
My(40sF) NP, Tommy(40sM), hates his job. Like A LOT. He's been talking about it for a while but hasn't really made any moves to do anything about it(this is relevant). He started training a new employee, Angelica. They hit it off as friends and started texting etc. He has other female friends so this is not at all unusual for him and I have no issues.
Things started getting a bit more than friendly so he brought it up to me and asked my advice. I advised he not date someone he works with, especially that closely. I don't inherently have an issue with workplace dating, however, his particular workplace is FULL of drama all the time. Like worse than high school, and he's already been burned by friendships at this place in ways that affect his job, not just socially. Also relevant that he's very trusting and tends to have an issue seeing red flags. Needless to say, I have legitimate concerns about him dating a co-worker but I'm never going to tell him he can't, because that's not part of our agreements or my own ethics around ENM. He agreed, told me he explained the situation to her and that he's down with flirting but it wouldn't be more than that unless he leaves that job and she was fine with that.
Here's where the issue starts. A couple days later in the evening he's suddenly invited to a coworker get together, which is pretty unusual but I didn't think much about it. He told me he'd be there an hour or so, gone 2 hours total with travel. He ended up being gone more like 5 hours. I have some anxiety around things like this so usually he's pretty good about checking in if he'll be gone longer than expected. I didn't hear from him at all. I was really upset when he got home but he apologized and that was that.
The next day he comes home and tells me that he's decided he's quitting his job and has actually started putting in applications etc and I was really really happy for him. He seemed really excited. Then follows that up with since he decided to quit he's now going to date Angelica and that they made out after work. I honestly didn't know how to respond to that. He tells me he has a date with her that night at the same place he met up with coworkers because she's only a couple minutes away from there... and I get really suspicious. So I ask him if she was at the gathering the other night and he said yes but he didn't know she would be there... and folks my red screaming bullshit alarms start going off hard. He insisted that's not why he was so late without a touch base but at this point I don't believe anything he's saying. He had to get ready and leave so we didn't really address things. He did give me a time when he would be home and as an extra step said he would check in by a particular time if he wouldn't be. He said they were just going to meet up and chat so he wouldn't be gone super long, but I'm already distrusting this for obvious reasons.
If he had been honest up front and said "I know she's a coworker but I still want to go for it" I still would have been concerned but I wouldn't be questioning whether I can trust him. We had a similar issue once in the beginning of our relationship with him saying something wouldn't happen and then it did and being gone longer than expected, but after the first incident I told him to just not say anything would or wouldn't happen and give himself extra time even if he didn't think he would need it and we didn't have an issue again until this.
He did come home on time... to tell me they fucked in his car. Now we only have agreements around disclosure after the fact, so normally this is fine, but he explicitly insisted nothing would be happening that night(which he DID NOT need to do). I'm not upset that he had sex... I'm upset at that point because it feels like once again he is not being completely honest with me. If he had said nothing and it happened it wouldn't have been an issue, but he explicitly said it wouldn't. We have been working through that but my trust is really shaky.
The last few days we've had some relationship challenges come up, not involving Angelica but the shaky trust is definitely contributing, and things are a bit rough between us. So I'm definitely feeling a little more sensitive than usual. We talked but didn't resolve anything and then took the next day and night to cool down with a loose plan we would talk again the following night(tonight). Granted we did not explicitly agree to that, so that's on me. We're texting about some of the things we need to talk about and I confirm I'd like to talk a bit in person tonight. He drops on me that he's going out with Angelica because their plans were interrupted a few nights before(the same night as our conflict but he swears that wasn't why), but we can talk after. I'm really hurt by this but I don't know if that's fair because we didn't explicitly say we would talk. I'm also not feeling great that he's suggesting we have a serious discussion about our relationship immediately following him hooking up with someone else. Plus, I don't really trust that he'll actually be home in time, even though he insists he will. It's complicated by the fact that if it doesn’t happen tonight it will be several nights until we have time to talk again and I really am not comfortable letting it go that long.
I'm realizing I have a distaste towards this relationship entirely. Not because of her or that she's a co-worker or anything like that but because it feels like he can't seem to be entirely honest about what's going on in regards to her and it feels like he's not necessarily breaking boundaries but certainly stretching them to their limits. It feels like he made himself a loophole to date her when he didn't need to. I'll also add that since that first week he hasn't really made much effort towards finding another job and the job market is really really bad right now. He's never had an issue being upfront with me about other people he has seen in the past and I just don't understand where any of this is coming from. Even if he is totally honest going forward I'm concerned I won't ever be comfortable with him seeing Angelica because of all this and how I'll deal with that. We're supposed to be getting married later this year and this is starting to make me question if I trust him enough to go through with it.
So reality check: Am I overreacting and just need to get my feelings in check about this? Or am I right to be concerned about this behavior?