You've already bought florals but I'll give my $.02 anyway.
If you wanted to pay respects to her then I think it would have been fine to go to the wake. Sign the book, say a prayer over the body (if you wanted), say a quick hey to him (if he was even there) or to his family members then you have option to bounce if there was any awkwardness.
Unless you know the funeral would be a larger service your presence may have been more "awkward" if it was attended by close friends/family or current girlfriend you may not know about.
Either way since you ended on friendly terms (& know he's having a hard time) I'd still call to give your sympathy. (A drama filled ex you last saw in court would warrant a different response).