same argument can be made of the other side unless there are signed docs saying other party owed this much money, etc. From my reading of case law- loans are a tricky thing to prove, esp. when they are to family.
To the OP- I'm not trying to judge you. It sounds like you were dealt a shitty hand by someone you trusted. But you're not going to find a lot of sympathy here when you think having to buy a condo instead of a house is hardship. There are people on this board who are/were willing to bankrupt themselves to fight for their children. I understand wanting to get the best financial deal- but I would also consider that you have to parent with the other party for next however long (I think you said you have fairly young kids?)...fight over money makes everything shitty. Someone is always going to lose and be bitter about it.
In my case- I was the total loser on the financial end of thing- and yes, was/am bitter about it- but this is why I told you go get some therapy (I did. It helps). It's hard wrapping your head around the expectations of where you thought you *should* be v. where you are...esp when the other person seems to have more. I was 40 and living with my parents- as a lawyer; so I could fund a custody battle while paying down 100% of the joint debt from the marriage (and A LOT of it because I made the unwise decision of using my line of credit during our marriage on my mat leave). Everyone has a sob story.
But if you have a good lawyer- listen to them. Put your best argument forward and get all your materials together- and then for your peace of mind- I suggest actually going through with a settlement conference on the financial stuff. A judge will give you their opinion. If you are on the losing side of that- you'll know. If they say you have a good argument- there you go. Then at least you can say you made the best case you could and make a decision from there.