Children sleeping with their mother

I was divorced about 2 years ago with my two boys (ages 7 and 10) living with their mother. My boys have been able to cope with the divorce well - my ex and I give alot of attention to them and explain as much as we can without blaming/badmouthing each other. My ex, I found out just recently, has been spending nights with either of the boys in bed with her. We are both over each other with no possibility of reconcilliation. My question is: how old should the boys be before this sleeping with their mother becomes an abnormality? The boys so far do not feel uncomfortable with the arrangement (the oldest does not sleep with his mother as much as the youngest)but a line has to be drawn somewhere - it is their mother that wants them to sleep with her, not vice versa. Thank You, Alan H.

• All mother's feelings are good by A freind, 1/10/99