How to prove date or spousal in court if the victim did not have injuries?

I agree who ever does that deserves to be punished but its a burden on the prosecutor to prove it beyond a reasnoble doubt.The defense could easily sat it was contensual espicialy she is his wife or girl friend and they were with each other for a long time.If it was the girl friend the defense would argue why did she come to his house.Because if i was a juror it will be hard to convince me unless there were injuries or a witness because sometimes women lie about or make there children lie about the father molesting them to get custody over them or if there was no children she might get angry and would like to get back at him or after he dumps her.I no that the minority of women do that because its unlikily to lie about being d.