I say again, you can not trust what she tells you.  You need to be sure, carved in stone facts.  She might suspect you are cheating & be doingthis to test YOU.  If there's something going on on her side, people can be good at hiding it from family (whose activities are known) but not from an outside observer.  

My ex was claiming to be staying over with her GF who was going through a rough patch...  I showed up at the GFs remote location about 10 PM...  we talked until midnight when the GF went to bed (her grandson was already asleep in the other room)...  while I got a pillow & blanket on the couch.  She was cooking us breakfast when the soon-to-be-ex called.  She was headed home & had tried calling our house to lie about where she'd been, but I hadn't answered.  She wanted GF to call until I picked up & tell the lie.  I know all this because her GF had motioned me to come next to her & held the phone off so I could hear.  
GF said "I can't tell him that."
STBX said "Why not?" (like you always lied for me before)
GF said "Because he's standing next to me!"
click

I never cheated or hobbied in those days...   I was personally able to track some of STBX's  movements, her GFs ex clued me in on where she was going, a cop buddy of mine followed her.  So I knew for certain what was going on.

I was severely underemployed at the time, had expended my savings supporting the STBX, so she no longer had an incentive to string me along.  It was her house...  I got my stuff out, Gone.  

Had I known & believed (I had been seriously in denial) I would have saved a bit of my dignity & some of my cash by stopping payments on her property.  (Bills can always be paid up afterward...  if things go the other way.  They can only charge you interest.)   I had paid off a large back tax bill before we married...  It was legally held in such a way that I could not even make claim for the addition or improvements...  I lost every dime I'd put in.  Everything was paid up and currant the day I moved out.  

We did not have credit cards in those days.  Cash is invisible.  I should have withdrawn cash from my account & held as cash which would have been a starting point.  I wasn't that smart.  I didn't have enough money to rent a motel room the day I moved out.  I moved into my parents unfinished basement in winter...  

I made another stupid mistake.  I sold off my gun collection to raise cash.  I opened a bank account with a buddy...  his name first...  so the ex could not claim it & it wouldn't show up in court ordered searches.  The buddy had an accident, when he couldn't pay the hospital bill they claimed the account.  It was in his name.  
I stupidly thought the INTEREST was important.  Preserving the PRINCIPAL is important.