They stop kissing on the mouth when come home or they a quicker peck.

They take more care in their appearance (clothes, makeup, lotioning hands more).

They say things to the children that are an attempt to devalue you, things they would never say before.

Take trips without and spend a lot of money on trip.

They stop talking about that coworker/friend they used to talk about regularly.

They fail to introduce you to someone at a social event.

Someone at social event they were just talking to fails to make eye contact with you.

New nickname in phone contacts or a name of the opposite sex with no last name.

Lock their phone or computer screen when you come around or wait impatiently for you to go away.

See them blush out of the blue when in thought.

Mention new restaurants to friends you've never been to together.