I'm married but I'm infatuated with a girl I work with

I love my wife and we spend almost all of our free time together. We've been married for over 3 years and generally have a strong relationship. However, lately things have been stressed out over money, sexual incompatibility and her daughter and 4 kids, which last year moved into our rather quaint 2 bedroom apartment. The girl I like I work with and we share a few common interests, physical attraction and there aren't a million headaches to keep our relationship from growing. The whole idea of talking to her makes me nervous but I find her irresistible. Recently, I asked her to go on a hike with me and she immediately said

Could you complete your post so that others can give you informed responses, please, Texan?

Do you want to break up with your wife or cheat on her? Do not think that starting a relationship with a new girl you will not have worries in consequence.