I have no advice about coke or soda in general, as they're not what tempts me (now give me a piece of chocolate and I'm sold). When I feel like drinking something good, I make myself a cup of tea. Some flavours are delicious, I drink lot of Rooibos tea as it tastes good without anything added, and is supposed to be really good for you. It's no soda though, I won't lie to you
I just wanted to say I really admire that you kept your weight off during all the stress and changes in your life. Yes, you hadn't been losing, but you hadn't been gaining either and that's awesome (or you gained very little). Myself I always gained back everything I ever lost, and some more pounds on the top of that. You're clearly very smart!