So you have a choice.
Make the best of the relationship now, don't sabotage it by pushing her away due to not trusting her, and find out down the line whether it a) works or b) doesn't work.
Or
Don't trust her, she gets fed up with constantly being accused of/thought of as a cheat, and breaks up with you.
The only way to know if you're "compatible" is to stick it out, there's no magic way of knowing in advance - but I can tell you now, if you don't trust her, it doesn't matter how compatible you are, it wont work.
So you don't trust her.
It doesn't matter what their previous relationship status was. You either trust her or you don't.