I agree with what you say Butternuts. And even if you do have a good family, from which you would not want to be distanced, as I do, I was thinking about it and I have to say, in the long run, practically, this kind of alliance would increase closeness of the family unit.
I have a daughter and my sister has a son who is a year and a half older than her. I also have a son, and my same sister has a daughter who is three months older than him. These two sets of first cousins have been each other's best friends since they were born. And when I first read about your quandary, I thought about it in terms of my family, and specifically, what would I think or do about it if my son or my daughter wanted to marry his or her cousin. And honestly, I wouldn't feel that negatively about it. I think my niece and nephew are great people- they come from a great family

, they have the same moral and cultural values, and in terms of in-laws- I couldn't ask for better people.
I'm not advocating this on a full-scale, day to day basis. But if/when you fall in love with someone, I have to say that I believe you should be allowed to follow your heart. Your family- no matter how wonderful it is- will not be able to fulfill the role in your life that your lifetime partner will.
I think it's imperative to be able to choose your life's partner based on
the fact that you love him or her and want to be with that person. Because in the US, where arranged marriages are not the norm, and family pressure to stay married is not so great and divorce is common- marrying someone you don't love or want to be with is almost asking for or insuring certain failure.
Besides the fact that it would be cruel to marry someone you are essentially settling for because you couldn't have who you really wanted.