help me how to get pregnant😔

hi everyone! i dont know where to start, me and my bf trying to conceive for 3 months now, but every time i told him, im fertile he got tense and can't have sex. Literarily he will stop having sex and just say sorry.. he say within a week if we do so still i can get pregnant but i think its really important that he do it the day im ovulating.. I also stress now and loosing so much weight .. i need advice on how to get rid of this heavy feeling that he really dont mean having a child with me...