I managed to talk to Alan today. He was confused, saying 'surely I did text you', but then he checked his phone, and ended up showing me the messages on it.
Basically, Bridget had been texting him, in a way that implied the messages were on my behalf, or from both of us (its a bit hard to explain without repeating their whole conversation). But in places she says things like 'Suzie needs to know what time you will be online'. But I specifically hadn't asked him for a time in advance as I didn't want him to make a promise and then stress if he couldn't make it, and I was at home all evening anyway, so it didn't matter to me. I'd told Bridget that he was just going to call when he was ready. Also, at the end of the conversation she said that I was very tired (which I wasn't) and asked him to promise her he wouldn't keep me up talking to me very long.
It also came up that a previous incident was because she had told him that she and I had discussed something and come to an agreement about it, when she hadn't even mentioned the subject to me!
By this point Alan was very apologetic, and I was feeling guilty that he was feeling bad about it (although still glad I bought it up), so we just changed the subject and moved on.
So, feeling pretty confused I called Bridget to ask her about it, and she said that it was because she cared about me she was 'watching out for me'. She said it was 'unfair' of Alan not to give me a time in advance, or to talk to me so late (I'm sure I've chatted to her just as late on occasion!), and that the agreement thing was 'in my interest', even if I didn't explicitly know about it.
I was getting a bit annoyed at this stage and said that I felt it was up to me to decide what was fair or not for me, not her.
She then started saying I was wrong to read her private text messages, which to be fair I kind of agree with. It just sort of spontaneously came up in the moment, with Alan going, 'look you guys were texting me about this...' and showing me, so I didn't even really think about it. In hindsight, I probably should have declined to read them and just said I didn't know the content of anything she was sending to him.
I then asked her if the three-way situation was making her unhappy or jealous, and she said there were some things that she felt she 'didn't have the right to ask for'. I asked her if she would be happier if Alan and I weren't perusing a relationship with each other, but she refused to answer the question.
So right now I'm feeling in a bit of a mess. I feel guilty that I may have been hurting Bridget by seeing Alan, but I don't want to stop seeing Alan (writing that makes me feel like a horribly selfish person). I also feel that Bridget has been being, er, manipulative, I guess? Its a bit of a stronger word than I mean really, just that she had been subtly (and probably not consciously) trying to control interactions between Alan and I, so I feel I can't trust her.