I’ve also been reading your other post, seeker.
You will tie yourself in knots if you try to provide a different explanation now (or in court) to that which you provided at the outset. As Barmaid has said (and which I think I mentioned somewhere along the line) even without the scratch to his face, trying to grab your husband’s phone constitutes an assault. Again, to confirm what Barmaid says, there does not even have to be any physical contact for an offence of assault to be proved.
If you plead not guilty there will be a trial. Your husband will be required to attend court and give evidence. If he refuses a witness summons will be issued (in fact most courts, in cases of domestic violence, now issue a witness summons at the outset). And the end result will almost certainly see you convicted. You will then be liable for much higher prosecution costs (probably around £300-£400 instead of around £85 for a guilty plea).
I know you believe this is all very unfair. But the facts is you did commit an assault, you had the opportunity to accept a caution (which in my view is a perfectly proper way to deal with this somewhat trivial matter) but you eventually declined. Unfortunately the CPS now has little option but to prosecute you.
Of course your solicitor will be much better placed to advise you than any of us here as he will have access to the full facts. But from what you have told us I would be very surprised if he gives you any advice other than to plead guilty. He will also be able to ensure your husband’s victim impact statement is available to the court.