(1)Don't get divorced!
(2) Stay in Sweden until the kids are both at least 18.
(3) Don't live with your husband.
(4) Live with your son, and possibly with your daughter, or split the time, as needed, desired.
(5) Live as close as possible to your husband, ideally a 10 minute walk away.
(6) Don't move back in with him if things get better, and they will.
(7) Turn a blind eye toward his sex life, if any.
(8) Don't date or be with anyone else until the kids are at least 18.
(9) Don't speak ill of him to people who know him in Sweden, especially his daughter or your son.
I hope this helps.