2 PS4s, 2 Accounts, 1 House. Please help me make sure this is allowed.

So my fiance and I own 2 PS4s. We each have our own accounts and both of them have PlayStation Plus. This is all in the same house on the same internet.

I was wondering if I could use my PSN account and link it to his PlayStation too? We were wanting to play split screen. However, I don't want to lose all the stuff on my PlayStation and I don't want either of our accounts to get banned for account sharing. If you could please provide some clarity on this matter. Thanks!