Frankly they are the same in most situations, expect in following cases:（ actually you can use both, but this is more authentic)（里means in the center of。 in a 3-D thing， 中 means in 。。among， in a abstract thing （在我的生命中，在我的心中/在我的心里。。slight difference。。） 1. 在海里（sea），在河里（river），在湖里（lake）。。。 2. 在空中(you should always use this form...always or 在空里 or 在天空里 is absolutely awkward，（sky）， 在宇宙中 or 在宇宙里（space， universe） 里 is more common in daily phrases， where is the rice？It is in the bag(在袋子里）He is at house 他在家里。。etc。

It has not big difference between those word. like ur example, 在我生命中is during my life, 在我生命里is in my life. I think 在我生命中is more formal. But If its 在...里面 and 在...之中. It has close meaning. but use in different situation. For example: Inside d room(在房间里面）has a table. we couldnt use 在....之中。 Inside our group(在我们之中） has a guy.we couldnt use 在...里面。 In a conclusion, 在..之中 often use on people. 在...里面 often use on project,product.

let me tell you ,first ,for you a learner who start to go ,it is difficult to understand the diffrernce between the two words,because even chinese people ,just a few can got it ,for a learner ,all you need to know is just the meaning ,more than the ditails,look at a question we must stand high and see the whole situation ,then we can grab the direction, actualy there no big diffrence about the word ,some times people just be used to the combination o f the word ，when you say love to your lover ,you can say 我的心里只有你，你一直在我心里，if you use the 你在我心中，the emotion will down, and dull,you kwon,the question is high level questin ,cool you bring it for disscussing

I don't think there has difference between "在我的生命中" and"在我的生命里”， i think you got the answer!

I think of it this way: 裡 just means inside， and zhong means within the bounds of （e.g. 其中＝amongst）。中 means middle and the etymology is of an arrow hitting a target, i believe.