Am I romanticizing what love should feel like?

I’ve been with my boyfriend for 7 years now altogether (we broke up twice). We talk about children and marriage and future plans all the time. However, when marriage conversations become more serious I always end up questioning whether I really wanna marry him or not. I only want to get married once so I would like to be certain of my spouse. I love him but it’s a kind of comfortable low-flame-candle-like love. Not entirely passionless but not exactly passionate. It’s what I would call “just fine”. I could be ok with this. So am I selfish for wanting a strong-wildfire-kind of love? Something with more energy where I feel more certainty about how I feel? Is something like that even real or am I romanticizing what love should feel like?

Whether you have experience in this or not I’d like to know what you would do. Thanks.