Welcome Meggy! Sorry for the circumstances, but if you are looking for clarity, light and support you have found the right place. As much as I hate addiction, I think I hate the word just as much. It is such a slippery, rotten thing to have happening your life.
IMO experience, it doesn't matter how we define it... if someone is using and it is impacting his/her life and those around them negatively... it's not good.
My AH has used for years. However, he would stand before you today and tell you he doesn't have a problem and he is not addicted. OKAY. My response to that is ... whatever. Then I don't like your choices and I don't care to allow those choices impact my life negatively.
Take care of you and remember that you deserve a happy, healthy and honest life. Maybe that is what you have... it's just my opinion... lots of hugs.