Do all women have lesbian relationships at one time or another in life- I think my wife is cheating?

I think most women at least fantasise about other women. some take it further, some dont, i know lots of women who call themselves straight, but have lesbian encounters, and i know lots of bi-sexual women. iv also heard of women who marry and have kids, but are lesbians, some cheat on their husbands with other women, others leave their husbands once the children have grown up.