Reconciliation after divorce/midlife crisis?

Hi I am new to this forum, and to forums in general, but am in need of some advice. Here is my story. I was married for 22 year, of which about 15 of them were happy. The happy years were great- even though we don't have a lot in common we seemed to fit well together, especially when our kids were younger. The things that we did not have in common were issues with money, how to raise our daughters, activity levels, among other things. The last few years, I guess these things came to a head, exacerbated by one of our daughters running completely off the chain and winding up in jail, then rehab, which she did recover from.

Anyway, my wife had what I would consider a midlife crisis, had an affair, started using drugs and smoking herself, tattoos, hanging out being the 'cool mom' with my daughters friends, and just being a 50-year old teenager. The affair, and the fact she really wasn't showing any interest in reconciling or calming down, caused me to move out and eventually file for divorce and start picking up the pieces. Post-divorce, I adjusted pretty well. I seemed to have kept our mutual friends, my daughters eventually grew up, and me and my daughters get along great now, along with new grandchildren, and life is pretty good right now.

The twist is that after about 5 years, the midlife crisis is past, my ex-wife didn't really adjust as well. She had a major failed relationship, lost the house, had to downsize, and works several part-time jobs (by choice), so is always having financial issues. I believe her when she says the drugs are finished, although she still smokes cigarettes. She says she still loves me and would like to get back together. I think she is sincere in this, but she still also seems to hold on to a lot of the past issues she claims to have had with me, and that occasionally comes out.

My dilemma, and it is very stressful and severe, keeping me up nights thinking about all of this, is what to do. Deep down, I really do love her, and don't want to hurt her, but am not sure we could get back together will all the time that's past and all the water under the bridge. I get along great with her family, which is important because my parents have both passed away, and her family was always very close. We are both now close to the kids (grown now) since she has 'recovered', so we are running into each other constantly, and I have to admit I still feel a spark. I'm not sure how my daughters would feel about this and haven't brought it up at all with them. And if I decline, what then will our post-divorce relationship be like? Currently we get along as good as can be expected, but I kind of get the feeling that's because she wants to reconcile.

Cons to getting back together would be things such as money- we have totally different spending habits. Activity- we have totally different philosophies, and I have really thrived on being more active post-divorce, where she went so far as taking up smoking. If there wasn't a history and prior emotions between us I doubt I would consider her my type if I just met her.

Weighing the pros and cons, it seems that I am better off by staying on my present path, in which I am pretty happy, and I feel well-adjusted. I'm not sure I can be totally objective emotionally however, because with somebody you have basically grown up with it's easy to feel familiar, and want to get the feeling of security back, and part of me always asks if we are truly meant to be together, even with all the incompatibilities and prior damage. Anyway, any advice or own personal experiences would be greatly appreciated, and may help avoid a nervous breakdown on my part!