There could be a lot of reasons you are not having sex as often. The first thing that comes to mind is your wife might be totally exhausted with two children being a full time mom and you don't say if she works? If she does, she is doing double duty working and taking care of the children as...
Tell this girl you have a crush on the guy at the table and want him there because he helps keep you and the other girl out of trouble and that you hope she will understand This way I wouldn't think you would hurt her feelings and you are telling the truth.
Only problem I see it you bought a Japanese car and supported a Japanese citizen when you could have bought an American car and took one of your neighbors off the unemployment line!