Lady;  this is a very interesting question that you have posted here.......

Falling out of love.....a very painful process to say the least....

I think I'll answer the easy part first.......YES I think it is possible not to fall out of love....it has to be or whats the use of being a romantic...but seriously I know a few older couples who are happily married and have been for 60 years or more and they still are in love.....and its not just their words but their actions toward each other that show the love.....But as to the rest...what leads up to falling out of love....I think one of the main reasons is that we as humans still have the bad habit of confusing love and lust and by the time we realize this most of the time, we've made the mistake of rushing into a more serious relationship......some of this stems from mankinds need to be (for lack of a better word) cuddled ........as for what you can do to head it off.....well I seriously don't think that there is anything that you can do........because as a romantic I will always believe in  Love At First Sight.......and that it's possible to find ones soulmate eventually........but I think people rush into things way to quick these days....and this leads to more instances of people falling out of love........As to knowing when it's to late.....I have NO idea...hindsight usually gives you all the answers of when you started to not love someone, unfortunately by then it's to late and the hurting has already started....The realization that you don't love somebody anymore I think comes when...... instead of a warm peaceful loving feeling in the presence of your mate......you feel uncomfortable and ill.......but truthfully I don't think you ever stop loving anyone unless the've been abusive and cruel....I think that your love for a person just changes.....from a close physical love to a more love of a family member type...you know the old saying I might have to love my family but I don't have to like them............this is really hard question and I've faced it from both sides....I don't know the answers but I know that I won"t give up on love because of it