Rephrasing based on William Lilly’s Christian Astrology page 316:
Look at the planet(s) in the 7th.
If Mars is there and not the significator of the partner, yes.
If Saturn is there, your partner loves a person but doesn’t not fuck that person.
If Jupiter is there, he/she has “much ado” to be honest. Perhaps this means that s/he makes a big fuss about his/her honesty and integrity. So, no.
If Venus is there, s/he flirts but doesn’t have one.
If Mercury is there, s/he had one but not now.
If the Moon is there, s/he doesn’t have one now but will have one in the future
If the Sun or North Node is there, s/he is faithful to you and has no lover.
Practical Astrology 