[Rivière]

This is just my opinion and you don't have to take in anything I've said but... yes he may not have said anything for two weeks, and that's really awful, but there may be something else going on. It's so easy to look at the negativity first, especially if/when you've been in countless situations where something ends up going wrong. There may be a logical reason for why he didn't message for two weeks. Sure you're seeing one another, but I think there may be a combination of your personal expectations in what you expect of him, and whatever's going on in his personal life. Have you actually discussed these sorts of boundaries with one another? Have you established any 'if I don't message in X time' rules? If you haven't, it may be a good idea to.

I've been in a relationship before where my partner expected me to reply to them within a certain amount of time. However, we never actually discussed any time limits or anything similar. I wasn't aware that he had this sort of expectation for me to reply. Sometimes I could go quite some time without saying anything. Not because I didn't care about him or didn't want to talk, but because we simply hadn't established that sort of boundary until it came up a year later into our relationship.

I can fully understand why you feel sad for the girl you were talking to. It sounds like she likes you a lot and wants to look out for you by suggesting you dump D. However, again, there may be a lot of things going on. Sure D says he doesn't want to commit to a relationship, but moving into a home with someone is a little bit different depending on context. He may be moving in with somebody but it doesn't necessarily mean he's committed to the person he's moving in with. He may be moving in with this person because of convenience and/or costs. Sometimes these things just happen even if we say we don't want to commit to something. It's so much easier to make comments about what we do/don't want until we're presented with a situation where we may have to break our word.

Overall, I think it would be a good idea to try and spend time with D and find out what's going on. It sounds like he's put a lot of effort into being with you and so far it doesn't sound like he intended to omit you as such. As you identify as non-binary, he may not have been sure which 'category' for lack of a better word, to reference you as. Talk with him, establish some communication boundaries, and go from there.