This happened to me - I found that when I froze milk, it didn't really last for more than a week, two at most, and then it needed to be brought to room temp fairly quickly (I mean leave it out of the fridge to warm up - I found heating it made it taste and smell totally 'off') - and I couldn't leave it standing around once it was at room temp (my fresh BM lasted at room temp for a few hours, nowhere near the epic timescales kellymom suggests.)
I know what you mean about separating - it's not a layer of 'cream' on top, that happens in the fridge, that's fine - it's more like curds, or the manky bits you get in cows milk when it's gone off.
I read a lot of stuff about how babies 'didn't mind' the taste of freezer milk, if it tasted funny, and I'm afraid I ended up not really trusting it. My milk tasted so vile it made me sick! As a first time mum, I was torn between assurances that 'babies don't mind' if milk tastes funny, and my common sense telling me that if it made ME feel ill, I wasn't going to feed it to my baby. After a week in the freezer, it got a 'painstrippery' tang - then a very strong sour taste, and then frankly, I think it was 'off', I really do. DS definitely took a bottle of fresh BM much better than he did milk that had been frozen and seemed a bit weird. I couldn't stand the idea that I might be away from him, and DP or someone else would be trying to force a bottle of 'off' milk on a hungry and confused DS.
Scalding was a huge pain in the arse, and I wasn't convinced it made a huge difference in terms of 'freezer life'. As it also destroys some of the benefical elements in BM, I really didn't feel it was worth it.
I was utterly gutted to start with - I found all this lipase stuff out when I found that my considerable freezer stash that I'd built up over several months was all off, apart from the most recent week.
I stopped freezing, basically. I found my milk kept fine in the back of the fridge for about 3/4 days (4 was pushing it) - 3 day old 'fridge' milk was actually better than week old 'freezer' milk (no tang or curdy separation). So I just used the fridge. For a while I had one bag of 3/4 ozs in the freezer as an 'emergency' feed, but had to remember to use that once a week, and then replace it.
It meant I had to plan ahead a lot more than I wanted to in terms of expressing - I loved the idea that a freezer stash gave me a little bit of flexibility, that I might be stuck in a huge traffic jam and take 3 hours to get back to DS instead of one hour but feel happier knowing there was frozen milk there if needed.... However, it didn't work for me.
Wish I could be more helpful, but all I can recommend is just using the fridge. Doesn't help if you wanted to build up a big stash, I know.