
Quoting
flyingron
Can you be charged: Yes. You could even be convicted. In Texas, forgery only requires that you made the signature without the authorization of the person. That you didn't benefit or the fact that the money went where "you" think it should have is immaterial. In fact, there is good reason the checks are made to require signatures of all the insureds.
Presumably if you had a power of attorney and she hadn't rescinded it you could argue you did have "authorization." Although the fact that you suspected she WOULD NOT have authorized it if you had contacted her, bodes against you. That's going to be your only out. Again, good faith and intent to gain aren't issues in the criminal charge.
However, I suspect any complaint she makes persuant to a divorce action is likely to be taken with bit of skepticism by the police. If the police come to ask about this, you should refer them to your attorney (which you appear to need for the divorce anyhow). You should not try to "explain" your way out of it like you did here as you'd almost certainly give incriminating statements (as you did here).