Depends on the god. From one like Hades, it would be... rather uncharacteristic. Not unbelievable - as it would be if you were claiming one of the virginal gods/goddesses was flirting with you - but uncharacteristic.

Personally, I don't concern myself with labels like "patron." I have numerous relationships with otherworldly entities. Labeling them is an afterthought. Have relationships with who you want. And by relationships, I don't necessarily mean romance... I mean any interaction between two individuals.