It's wrong to take advantage of one's partner.
Alex is sleeping in his bed with his wife Jen, and he is sexually aroused.
Alex wants to get rid of his sexual arousal.
Alex asks Jen to have sex and decides to just masturbate after she says now.
Alex has sex with his wife while she is sleeping and without her consent.
Jen trusts Alex to not force her to have sex when she doesn't want to.
Jen feels violated and doesn't feel safe sleeping in the same bed with Alex anymore.