All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is not permissible for the wife to refuse her husband’s call to bed (for sexual intercourse) unless she has a sound reason, like being in menses or being sick and so forth; for more benefit, please refer to Fatwa 88547.
What you mentioned is not a sound reason for refusing to have sexual intercourse with your husband unless you know for sure or predominantly think that he may not perform the obligatory Ghusl (ritual bath) without any sound reason. It is better, in this case, to discuss the matter with him so that things will become clearer to you.
Allaah Knows best.