Oh hon, addictions are so hard, whether it's smoking, drugs, food, etc. I feel for you so much!
One pack of cigarettes does not mean you have failed. You recognize that you want to make a change, & that it is hard. That is the first step!!
If you've already opened the pack & had some, it's still not too late. Make adjustments going forward.
Try to identify with WHY you smoke. Is it to relax? To de-stress? Do you feel self-conscious -without- one in your hand when you are around people?
You have reasons NOT to smoke. You listed some in your post, & I'm sure there are more. Try to find ways to motivate yourself... a calendar where you mark off with a big smiley face the days you didn't smoke. A whiteboard that lists "XX # of days without a cigarette" like an OSHA safety board.
Do you use social media, like FB? Post that you are looking to quit! Get people's support. Ask your best friends to check in with you every day to keep you on track. TELL your husband about your struggle today, & elicit his support.
You also mention wanting to be in better health. Start by scheduling yourself time each day to be active (10-15 min to start, something you can stick with). And keep a journal about how you are feeling, how hard it is, & how easy it becomes. Give yourself these tangibles to keep yourself on track with your success!!
People are infinitely more successful when they change their surroundings to meet their needs. Below is a link to a blog response for a question about overcoming addictions. (It's a great blog about all sorts of life issues, but this particular response is specific to your situation)
http://now.eloqua.com/es.asp?s=567&e=199938&elq=d...
We know you can do it, YOU know you can do it. It will take time, determination & a little help from your friends (sounds like a Bob Dylan song, eh?).
Now, if you haven't yet, go throw away that pack!! How on earth will you regret making such an important first step towards something YOU want?
We are all pulling for you!! T.