Based on my personal experience with the process, and having been involved (peripherally) in the trials and tribulations of some peers and subordinates, I support your retention of a lawyer. It's essential that any agreement be done right from the start and that it contain as much detail as possible. Division of assets (and debts) accumulated during the "marriage", and custody of and access to children are usually the main sticking points.
I'd recommend that, once the parties have agreed to the form and content of the agreement, that it be brought to a judge for his or her sign-off thus turning it into a Court Order. This can probably be done through a motion on consent (i.e., both parties agree).
Regarding pension, the Pension Benefits Division Act applies. If your significant other was indeed considered to be a spouse under law, she has the right to 50% of the contributions made from the date you were "married" to the date of separation. There's no ten-year caveat.
I used my lawyer as my staff officer. I gave him my intent on all issues and insisted that he obtain my approval for all communications between him and counsel for my ex-wife before he sent them, just to make sure that my intent was being followed. Always remember that you're the boss, not your lawyer.
Try your best to figure out on what matter(s) you will fight to the death, and tell your lawyer what it is/they are. The rest are, in relative terms, fluff.
Lastly (and perhaps, most importantly), do your best to shelter your child from what's going on. Don't badmouth Mom if there's any chance the child may hear (even second-hand). If she does it to you, don't respond. Document it, and if it gets bad enough, you may have a case for parental alienation (although the burden of proof is very heavy). Kids need their parents to be adults.
Good luck to you.
