I have no ethical or moral issues with Izzy using her own embryos -- Alex signed away all rights -- they were hers to use or not. and she did.
Deep down Alex didn't really change. I contend that none of them have really changed.
I always felt the show did a good job of showing us that while Alex loved Jo (enough to marry her) and like he said -- at the time he meant it -- that he was never IN LOVE with Jo -- if that makes sense?
Plus the letter to Mere made it sound like the moment he laid eyes on his children -- he fell deeply madly in love with them -- enough to give up everything for them. Knowing way too many dead-beat dads -- I was OK with this as well.
Sorry that Jo is the one who gets dumped. There was no way to write this without someone getting hurt. I am OK with that character being Jo.
The actor is gone -- that is a fact -- and the writers had to do something to explain the characters departure. Personally, I liked their choice of giving Alex a happily ever after scenario.