Work hurts my heart

I'm at a cross roads of sort and I haven't got a clue how to deal with it. I really want to tell my job "go to hell, I’m not working weekends or evenings anymore, deal with it" but might get fired. Let me explain the back story:

I've been working at DirectBuy for 5 years. In that time I’ve worked almost every position in the store, and am easily one of the most useful bodies onsite. My focus lately has been assistant service manager (which is a retarded title because a) there's no service manager any more, so who am I assisting? and b) I've been given all kinds of other responsibilities on top of the service area, so it certainly doesn’t do justice to what I do.

When my daughter Aurora was born I took 6 months off the be with her, something I am very happy I did as I think I have a better bond than some dads, and understand the "stay at home crazies" better than a lot of guys do. After I came back from this i was working as the assistant service manager, not working evenings or weekends, and it was good.

After about a year and half, they asked me to start working weekends and evenings. I said yes because a) it wasn't many weekends and b) it wasn't many evenings and c) I did think it was fair that i take part of the load. As these things happen though, they've started adding more and more. It's not tragic or anything - I’ve worked 8 out of the last 22 weekend days - but it is bothering me. Particularly because service doesn't have anything to do with the weekends. There are 2 managers (one accounting, one HR (although really, she just does everything)) that never work weekends or evenings. The argument is that their positions don't require weekend days. Well why the hell does mine then? Service doesn't need to be their on the weekends any more than those two do.

Baby number 2 is enroute and the pressure from the wife is building that she needs me at home because she's not taken being pregnant well and really can't handle the current child alone that well. I don't know what my own rights are and what the stores rights are. I like to think that even with restrictions on my availability I'm worth keeping - I give a lot to this store, and bring a lot to the table.

This kind of came to head when I sent an email to my boss and another manager and basically said "me and this other manager have been working more weekends lately, so I'm hitting you a bit harder on the next schedule". I was just trying to explain why she had an abnormal amount of weekends coming up. Well she blew up and sent me a rather unprofessional email, which just stressed me the hell out, and said she'd do the schedule from now on to ensure it's "fair". So now what? There's nothing in paper anywhere about my job and what hours are required for this position, so can they say "these hours are a necessity, work them or you are fired"? I think they can. Although the job was worked for quite a while without this being a necessity, so is that an argument that it's just them being pissy??

Would they fire me though? That's more the rub. To be honest, I can't see getting another job with the hours flexibility that this brings - i think i could get close to the same coin, but would probably have to work even more evenings/weekends. So why am i fighting this so hard? Mostly its the unfairness of it all - why should I have to work these shifts when other managers who are no higher on the totem than me don't.

It's extra frustrating because working evenings and weekends basically eliminates productivity from me, and often I'm to busy to want to lose this productivity doing, you know, my job. It's wasted time and that's frustrating when one major complaint is we take to long to deal with things. We'd take less time if our managment team wasn't wasting time workings evenings and weekends that all we are there for is to say "there there there" to members. half the time i work reception while someone types order, the other half of the time I wander the floor just helping members, something that any number of trained staff should be able to do. There's no reason why the team leads can't just take the information from the angry person and let them know they will get a call back on Monday.

So how hard can I fight this, and how far should I fight this? that's the question. I'm a reasonbly smart guy but labour laws are like mumbo jumbo to me. I'll keep looking though to see if i can hammer out what rights I actually have in regards to schedule. I'm pretty sure workers don't have much rights though.