Thanks for confirming. The difficulty she has is that as they are both on the title of the property they are both legally entitled to occupy the property and he can only be removed by agreement or if there is an injunction preventing him from living there, for example if there is domestic violence.
As they are living together, he cannot apply for "sole custody". For your information if either of them were to proceed to court it would be for a child arrangement order (for residence). A court will only make an order if it is in the child's best interests and if there is no benefit to the child if an order is in place, then a court will not make one.
Given that it is likely difficult for them to both live under the same roof due to his infidelity, then she should seriously consider her options which will include:
-Selling the property, dividing the equity between them and then rehousing herself and daughter or applying to court for her an child to remain in the property until the child reaches a certain age (eg. until end of education). This second option may prove difficult depending on their full finances.
In the circumstances I would suggest that you make a referral to an independent mediator (you can find local ones here: familymediationcouncil.org.uk). The mediator will assist you both in reaching an amicable agreement that is in the child's best interests.
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