Seeking advice from committed guys.

I want to hear from guys who have been in one relationship only. Same person, always for an extended period of time. My boyfriend and I have been together 3 and a half years. We love each other beyond words and there isn’t any doubt at all. We’re both quite happy with each other. But he has only ever had me - I was in previous heterosexual relationships and it has come up. For the guys who’ve only had one - what’re your thoughts? Has there ever been desires to stray? Maybe consider an open relationship? Spending time apart to explore? Or has The One been what you need, want and desire?I don’t want my boyfriend to feel suffocated. I want him to be happy. I’m afraid something might come out of this and I don’t want that...he is the person I want to spend the rest of my life with.