We too will have been married 40 years this year. We met when she was 16 and I was 20 and married at 17 & 21. I was still a virgin. She was not. She cuckolded me and lost her virginity to another in the middle of our engagement. Regardless, it didn't happen again until year 7 when she had her first affair that started the whole thing. First, he came with us on a vacation that we left the kids at grandparents. Then for the next 2 years, she went on several trips with him alone and left me with the kids. I was not happy about it but it was also horribly exciting. She's done overnights or weekends alone since then but not whole weeks. I'll say that after 40 years you should be able to make your husband see it your way and get his approval before hand. And also after 40 years, there won't be much he can do about it if you do it without it anyway.