Sad story but it's all about perspective.
To be sure your situation is a sad one but not uncommon I'm afraid. My mid life career change to ATPL didn't work out at first either but I went back to my old IT career as a contractor, earned fab money for 18 months, did a bit of private flying and luckily got a call from Flybe.
Been flying 4 years now for them and am happy I made the career change even if my bank manager isn't. Truth is though that even when you make it to the right seat of an airliner with a major airline after a while you start to want to work less days for more pay on heavier metal - so I'm still frustrated and so are all the co-pilots I know. Truth is that we work bloody hard to take home £2000 a month, it's not enough for a good lifestyle and the time off stinks (a weekend is one usable night here). I suspect if I managed to get into one of the quality outfits - charter/BA/Virgin I might finally sit back and think 'I made it' because it doesn't feel like it from where I'm currently sitting.
What I'm trying to say is that this job may not live up to your expectations anyway if you end up working for a LCC (except maybe Easyjet) because there are just too many people earning more money easier in other ways.
My advice for what it's worth would be to get yourself the best paid job you can in the meantime. Take 6 months off from worrying about flying, enjoy life, go for a beer, take a holiday and then reassess. Sounds like letting the rating lapse a few months is no biggie. I actually took over 12 months out from applying to airlines and had a bloody good time during my IT contracting 18 months and not thinking about it really helped me get it in perspective because the whole thing had made me completely miserable. At the end of the day your hobbies, family, girlfriend, kids are what's important not bloody flying a piece of metal around the sky 4 times a day and missing your kids birthday while you do it!
It really isn't the be and end all. In fact it's no more enjoyable than doing lots of other things like being a tree surgeon, selling fancy cars, working as a photographer, being cabin crew, working in the military. There are loads of interesting things to do with your life that don't involve getting up at 4am and feeling knackered most of the time!!
Anyway, hope this helps and I wish you the best of luck. Incidentally the tree surgeon one is interesting - I talk to one of those regularly and he loves it - fresh air, more work than he can handle, countryside, work when he wants, loves wood, a real man's job, using his expertise and more money than I make doing this... Makes you think doesn't it?