This is a follow up for a different question I posted earlier this week. Here is the brief background story: There is a guy I work with that I know likes me and was talking to me a lot for a while and asked me out a couple of times but never committed to a plan so we never did. After the holidays for no obvious reason he started retreating and stopped communication with me. He sits right next to me every day but speaks to other people and does not acknowledge me anymore. He is very quiet and reserved so he's hard to read and normally doesn't speak to people unless they address him first (although he used to start conversations with me all the time).
As we got to talk more I started to like him as well and was enjoying getting to know each other. A few weeks ago I invited him to a dinner party I'm hosting this coming weekend (that was while we were still talking a lot). My dinner party is approaching soon and my question is how to politely ask him if he still plans on attending since he never confirmed RSVP. This is a little tough for me because I like him and don't want additional awkwardness between us as we see each other every day at work and I don't understand what changed.
Last time I texted him was last week and he confirmed that he's aware of the date of my party but didn't say anything beyond that. I want to know how to approach the topic of the party without making him uncomfortable, I was also considering asking why he cut communication with me but I'm unsure how to go about that too.
So, what is the best way to ask this person about attending my party without making him feel obligated or pressured?
I asked friends for advice but most of them said to assume he's not going to come or forget about it and don't even ask. Some said that maybe he's shy and scared to talk to me but he was able to do that before so I don't know what to think.
*another side-note: this guy's room mate (who also happens to work in our office) invited me to a new year's eve party which I declined because I was nervous to be around him when he started pulling away so it might be something related to his behavior too but I don't know that for sure.