assuming if you didn't say no that you are interested in this man and had even considered going on a date with him. Is this what you really want? I can't tell you what to do because I don't know enough about you but don't destroy your marriage on a whim because you might regret it later. It's your decision but think about it carefully first.
Yes it is wrong,biblically that is adultery and it is against God's commandments,one needs to stay loyal to the person he/she is married to under any circumstances
If I may say the answer of the lady will differ on the relationship that she is having with her husband if bad she might agree to the date if alright then she will not do so