My husband had left the marital home after starting an adulterous relationship with a work colleague. I have been left in the marital home with my 17 year old (18 in april) who is a full time student. Husband has offered to pay half of the mortgage and house insurance until property is sold. Do I have to sell and should he be paying mortgage while my don vompletes his full time education ( course ends may 2014). Please advise as I have had conflicting advice from friends. I work full time and can probably manage at a push - just need to know what I would be entitled to. Thanks.

First, any question on law needs to include your general location as laws vary by area. Second, how long has he been your son's stepfather?

You don't have to sell the house, but you may have to buy him out if you want to keep it.

A stepfather has no responsibiltiy to support a stepchild.

A stepfather has no responsibiltiy to support a stepchild.

As I recall, there were some situations in some states where a stepfather was required to support a stepson if the father clearly acted as the child's father. Its unusual but it has happened. I tend to doubt it will happen here, but without knowing more its hard to say for sure.

My husband and cohabited from my son being 2 then married when he was 6. He is now 17 and regards my husband as his father.

And where are you? Without knowing we can't check the applicable law.

Your son will be an adult in 2 months! Are you looking for support for the time between when he left and April? Certainly none after he is 18.
Questions about the house, your son, and other assets and debts will be determined by divorce court. You NEED to get a divorce in order to have a chance of keeping the house.

A stepfather has no responsibiltiy to support a stepchild.

One place this can happen is in Canada. But as far as in the U.S. it would be highly unusual for it to occur as commonly the step father has no ties unless the child was adopted.

Normally no he will not pay any support for the child, there are a few cases but it is not common in most places. If he does, most likely it would end at 18 anyway.

On the house, he does not have to pay you a penny toward the payment if he does not want to, he can let it go into default but how owns the house, will be up to the divorce court.
If you can not pay him for his 1/2 of the house, most likely it will be sold.

You may get spousal support depending on your income and location but not till ordered by the court

And where are you? Without knowing we can't check the applicable law.

Living in uk.

Even in UK you must file for child support/ maintenance/ against the biological father. You may ask for additional support from the stepfather only if he has paid some additional expenses like private tuition, sport activities and so on...