Yes, ESPOUSING is a Scrabble word!

Letter values in Scrabble US: E 1, S 1, P 3, O 1, U 1, S 1, I 1, N 1, G 2.

Is it a valid word?

ESPOUSING is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

choose and follow; as of theories, ideas, policies, strategies or plans
take in marriage
take up the cause, ideology, practice, method, of someone and use it as one's own

Also: get married, hook up with, get hitched with, sweep up.