I assume you are a joint owner - i.e. your name is on the title deeds. If so, you have just as much right as your ex-partner to have access to the house (or to live there if you wish). He has no right to deny you access (or to remove your belongings) without a Court order - which he would be most unlikely to get. If you can't get him to act responsibly on this, you may need to have a solicitor to advise you and initiate whatever action is needed.
Also, he cannot sell the house without your agreement and your signature.