is we use Hangouts which works on Apple products, Windows computers and Android devices. My work computer is windows and we have an Apple laptop at home. The only downside is my wife has to use hangouts to send messages to me and messenger for everyone else. But apple doesn't allow their messenger to run on Windows devices so there isn't any other solution and she knows I will see her messages right away by using Hangouts.

Apple has excellent products but I have never liked being stuck in one ecosystem. I understand why people would stay with them though. I wish Apple expanded to be more cross platform compatible like Google. But that kinda goes against their current business model. Maybe some day.

Edit: Hangouts also lets you see if the other person has viewed the message.