After being together for a long time, it’s normal that sometimes you start to feel bored with each other. My advice is to open up to him about what you’re noticing, because he might not even be aware of it due to how busy he is with work.
You both need to have quality time together again so you can reconnect. Also, don’t forget to take care of yourself—make yourself look good and feel confident. Try to dress up and take care of your appearance so the spark between you two can come back, just like when your relationship first started.