Hi Stacey,
I think Squirrel has the best solution to your situation. I went through a very similar thing to you 12 years ago when I first came over here to be with my fiance. After a couple of trips out of the UK and back in, I got picked on by a very grumpy immigration officer who told me I couldn't keep coming in on a tourist visa (even though I was supporting myself, not working, etc.), and he gave me a stamp only allowing me to stay 6 months from when I had FIRST come in.
I got around this by applying for a fiance visa, although I never did get one as it took forever! In the meantime, while they were processing my application I was allowed to stay here as long as I wanted (but of course couldn't leave).
With regard to coming back into the UK after your wedding, you will need to go to the consolate in NY and get a letter from them. You do need to have your marriage certificate to do this. Again, I had the same problem - was getting married in the US on a Saturday and flying back to the UK on the Monday after. I was told that if I didn't have this letter, they didn't have to let me back in the UK. The solution was to have a "secret" wedding at a registry office here, and take the UK marriage certificate back with us and present it to the NY consolate. Most of my family still don't know that my husband and I were legally married BEFORE our wedding in the States.
By the way, I also used to live and work in Boston. Went to college at MIT, then lived in Somerville near Porter Square. I really missed Boston when I first came to England, but love Bristol now.
Best of luck with everything!
Cheers,
Suzanne