I’m afraid @Trillian is right. The reason we become bored with someone is because the relationship is having a problem. The interaction is not as exciting and communicative as it once was. Perhaps you are feeling taken for granted. Like he marches in, sits down, pulls down his fly and says “suck me,” without any other words. And this happens not just once, but over and over.
A relationship needs to change and grow, and lovemaking needs to be a part of that. There are two people here. You both are responsible for making things fun.
I think you need to tell him that what you are doing isn’t working for you and is making you resent him. If he does not want to change and make it better, that’s a bad sign. But if you have a working relationship, then when you tell him, he should be very concerned and want you to regain your pleasure at pleasuring him. I suggest you two talk about it. Hopefully in a fun way. Don’t wait for a fight to bring this up.