Re: Falling out of Love…
1: There is a slight possibility for love to happen just once for a few. I for one fell in love with a girl for the 1st time when I was 24 and if that would have continued it most certainly would have been the 1st and the last time for me.
2: Real love is supposed to be unconditional, with no strings attached.
3: Probably yes, possibly not. Depends on what part of it one considers it to be overrated really.
The above are just personal preferences and certain experiences really. I respect your opinions regardless. 
On Topic: Yes, falling out of love is very much possible. At the same time one i also expected to try their very best to make it work, the harder the quest to solution, the fruitful the result. Happiness and pain is part of life/love and technically every relationship has to go through it too. Apparently the stuff you have mentioned is quiet hurtful and I completely feel for you, but I just cant really base my opinion on mere few words and have my share by helping to make or break a relationship. Relationships prior marriage are simply like glass houses, takes ages to build but seconds to break.
I can however suggest for the 2 of you to sit down and discuss everything in absolute detail and mutually try your level best to help overcome your issues. May Allah SWT be with you.
My apologies if the stuff I said was not helpful enough.