These will vary according to your individual circumstances and you should seek legal advice regarding any joint assets you have with your ex-partner.
If you're married, you'll need legal advice about the possibility of a divorce settlement.
If you are cohabiting you may also be entitled to a settlement depending on the circumstances. You can phone Rights of Women on 020 7251 6577 for free legal advice and you may need to consult a solicitor who specialises in Family Law.
If you get divorced or formally separate from your husband or cohabitee (i.e. a person you lived with), you may be entitled to a lump sum settlement, a share of your ex-partner's pension and/or regular payments. You may need to go to court to get these.
Other things to bear in mind
Remember the Child Support Agency now deals with child maintenance claims. These are assessed according to the non-resident parent's income and situation (for example whether your partner has other children to support and whether he's living with another partner).
If you are working more than 16 hours a week you may be entitled to Child Tax Credit and Working Tax Credit. For further information on this, phone 0845 300 3900.
If you leave home and bills are in your name (e.g. gas, electricity and telephone) remember to tell the relevant companies that you no longer live at that address.
If you have joint bank accounts or credit cards tell the relevant bank or financial institution that you have separated and ask them to remove your name from the account. This will stop you being responsible for any bills or overdrafts which your partner may occur.