Widowed and dating problem

I am a senior person dating a 70 year old man. We are both widowed and knew each other before spouses died. Have been dating for a year off and on. Relationship was platonic until two weeks ago when he came to visit me. For six months of the year we live in different states I am now falling in love and he dates two other woman but is not intimate with them. He is very open and honest with me We will now be in the same state for the next five months and his can I sleep with him and then he takes someone else out for dinner? He says because we live apart for half a year he can't stay in the house and be alone. I understand that but I just can't learn to share him