Welcome! And I can't believe how identical we are. I'm the pretty much the same weight, and if you substitute potato chips with chocolate then I'm all with you.
I think, in the beginning, the best thing is not to go crazy on the workout. Instead just go for a walk (you even have a boyfriend to walk with oh most luckiest of all people), do something easy. If you start off with working out three times a week then you'll get bored with it after a month (like you said) and it's all a waste.
My biggest breakthrough came when I realized that I hate gyms. I'd much rather swim (pirbadet, ftw) or go for a walk. To me that's just as nice, plus it doesn't feel like it's being forced on me. I really really hate gyms. And biking :P