having become a young widow, I can now offer a unique perspective. If there is any amount of mistrust in the area of blending finances, perhaps counseling is needed. I didn't mistrust my husband, but we did take advantage of our youth and we never got around to putting each others name on the accounts, updating beneficiaries, or making wills. I am learning the hard and expensive way about probate and the other consequences to our actions.
Separate accounts are fine. We used one account for the responsibilities and the other for life enjoyment and it worked for us. Just be sure that no matter what you decide, you do the responsible thing early. If you want completely separate accounts make sure you make them pay on death to each other so that you are not blocked out or loose it completely if the worst should happen.