Caught In A Lie About The Graduation Party

I'm a professor at a small liberal arts college. I've been engaged for almost six months now to the dean of students. Everything's pretty good, except for this one thing that keeps gnawing at me. We were planning our wedding for next year, but lately my fiancé has seemed more distant and preoccupied. Last weekend he asked me about some recent events on campus, like the graduation party I was supposed to oversee as faculty advisor. The student committee came up with a great event, complete with live music, food trucks, and even a guest speaker who's really popular. But I didn't tell him that I got distracted by personal stuff earlier this week and didn't check in on things like decorations or catering arrangements until yesterday, when the setup was almost done. When he asked how everything was going, I fibbed to him and said it was all handled perfectly, I even told him there were a few extra funds left over for refreshments. The truth is, there's no surplus money. We're actually running on a tighter budget than we expected because of some unanticipated expenses earlier in the year. This lie about the party's finances is really bothering me now that he found out I didn't attend a committee meeting yesterday when I said I did. He thinks everything is under control, but it feels like there are secrets between us building up. I feel terrible and am not sure how to approach this with my fiancé or even if I should tell him at all about the extra stress on me right now. Sometimes I wonder if he might be starting to think less of me because I didn't step in until almost everything was set, but then again, maybe he's just preoccupied and doesn't care as much as he used to about little things like that. This whole situation has made me realize how small a lie can make you feel. It’s just such an inconsequential thing compared to what matters most, our marriage plans ahead, yet it still casts this dark shadow on everything.