Why Can't I Do It Alone?

As I've said in before, I'm currently engaged to a guy I love very much and love spending time with. It's great fun, but sometimes I like doing fun things on my own. So, for the past few weeks, I've been doing more by myself. I've eaten out, gone for walks, and other things I could probably do with somebody else, but just really like doing alone too. Usually, nobody really pays attention to me. I just blend in with the background or they assume I'm waiting for somebody.

The only time this is not the case is when I go to the movies alone. Loud gasps all around, oh the horror! - I know. I go up to the ticket counter and ask for one ticket, get whatever snack I want ("just one, thanks"), and find a seat without worrying if one of them is taken. The first time I went to the movies alone, I thought I was imagining it, but now that I've done it more I'm convinced that some people are really surprised to see me alone.

I once spoke to a single friend of mine who seemed embarrassed at the thought of going to the movies alone. She could do pretty much everything else on her own, but the movies? No way! That's just... weird! Only lonely, old people do that. Even when telling my guy about going to the movies alone, he suddenly acts as if this somehow means I'm lonely and he's neglecting me.

I don't really get it. Is it just me? In college there were a couple of times when I went to the movies on my own. If it was going to be a hassle to coordinate with other people and I really wanted to watch something, I went. Why is it such a big deal, why can't I do it alone?

Does any of you have something you do on your own that people usually do in groups? Do you find that being in a relationship increases that expectation?