How do you let your SO know you love them?

Lately my relationship has been rough lots of arguments, doubts of love for each other lots of anger he is convinced I love my dog more because I show her more love then him, we have been together almost 5 years things are just getting routine I guess what’s are some things I can do to show I love my fiancé? I used to leave little notes but I feel they just go unnoticed. I just need to “spice things up” in the love department. “Get back” in the honeymoon phase kind of love if that’s even possible. All helps appreciated TIA had to choose this Gif because I love Doug lol.