I’ve been working with Lord Asmodeus for some time now, and he has become my patron in my demonolatry paradigm. He is a very kind and loving god, even though he was the Zoroastrian deva of wrath and the Goetic spirit associated with lust, and when given respect is extremely protective of his followers.
As Lady Eva mentions, he has a specific agenda that is somewhat separate from other Goetic spirits - he seems to not crave fealty so much as exist as a guide for those who seek his guidance. He has received much bad press over the years, and if worked with you really need to get into the relationship with an open mind and prepare to be tested.
It is a belief within demonolatry that Asmodeus was/is married to the goddess Lilith at some stage, but this could also be confusion surrounding who Asmodeus actually is - some see him as an aspect of Samael, who is also recorded as being married to Lilith, others as an early Satanic model.
All in all, Asmodeus is a very rewarding god who helps and protects those that show him honour and respect, but be prepared to experience massive fits of anger and overriding desires for things that may once have disgusted you.