What kind of a love spell was it? I'm assuming it was a spell you cast on another person, the object of your affections, versus one you'd cast on yourself to attract a new lover?
You could assume your magic was in some way lacking due to lack of experience, a crummy spell, or some mistake in manifestation (thinking the spell to death, unconsciously sabotaging your work, etc.).
You could assume that the Universe is telling you NO!!!, not gonna happen with the target of your spell, so sorry.
You could assume that the Universe is sending you a more suitable mate, and therefore trust Spirit and go with this person you *are* attracting.
Or you could also try, try again. Some people just have to keep trying, at least for a time*.
*I was taught that when working love spells you should set a time limit, as in i'll keep working this love spell on this person until X amount of time (one month, six months, one year, etc., whatever Spirit leads you to), and then i will *drop* the spellwork, over and done, time to move on, a hard and fast deadline you keep to. This is advice i give to every person who decides to do multiple spells over a period of time on one particular person.