I'm with cinder on this one. Simply getting into the relationship does not mean the person is godsent. Nor does rejecting a relationship mean you are refusing a blessing. Relationships fail for a variety of reasons.
If a woman prays for a husband and guy that's known for beating women asks her out, is that god sending her a man that beats women? Is refusing to date him rejecting gods blessing? She did pray and he did show up. What if he claims he's changed and she dates him then he beats her. Is she rejecting gods blessing then?
No. People come and go in our lives. Relationships do as well.
Unless you are referencing a specific situation, in which case you should make that more clear and clarify the question.
What i see as more common is people making bad choices in starting relationships and telling themselves, and others, it's from god. Then when it doesn't work out they're shocked that it didn't work and blame god. Ignoring that everyone told them it was a bad idea. I see that to be much more common than genuinely good relationships forming and people randomly leaving them.