How to fall in love with your daughter father after 21years he wants to marry me .wht do i need to do to make?

sure that he im doing the right thing,i do still care about him,and i would love to be his wife after 26 years of knowing him,also how do i know that he really wants too!i say that because he said it before and i just want to make sure its the right thing to do i love and care for him ,also he's n baltimore maryland n im in easton,pa so it would be a big change if i moved there or he move here alot to talk about it,also do u think i should have sex to know if the fling be the same from 8 years ago,when i last slept with him ,i need womans advice strong ones that been there thank u dee