Not entirely sure why your DH laughed, or why he said you cannot wear a tshirt... I think blue is entirely feasible. Given the range of colours in the skirt, I would pick one and go with it, otherwise to add in another colour would be a bit OTT. I think blue would work well, though I think a clear blue would be better. And t shirt would work fine as the skirt is busy, pattern wise, so a plain, simple top would be better. I think!
It's really hard to say without seeing the tee. Too loose would look odd unless you're very tall and bony. But too tight wouldn't work either. I'm not against the idea of a tee per se but it needs to be the right one. I also wouldn't go matchy matchy on the shoes, I'd stick to black.