During her stay in 'That Time I Got Reincarnated as a Slime', Rimuru was fortunate enough not to shackle herself romantically to anyone. But--and yet--her allies had no shortage in admiration for another individual. Not to mention reverence.
Slipping into the role of a leader, Rimuru would appear somewhat cramped for time to get involved in matters of love. He cares not for these things…Toward peace making, nurturing future generations, and overseeing the growth & development of his newly born nation.