A Muslim man has proposed marriage to her, and she committed a sin previously

I am a 25 year old woman, who has had a Muta'a marriage at a young age. I understand that the Sunnis believe that this type of marriage is haraam. The reasons why I had that marriage are too many to explain here, but the circumstances under which it happenned make me still question how great a sin it was, and sometimes if it is a sin at all. May Allah forgive me, and show me the right way, as living in the world so different from the days of the Prophet makes it sometimes difficult for me, as both a Westerner as well as Muslim, to distinguish between the haraam and the halaal.
I now know a Muslim man who has never been married, and who would like to marry me. I am concerned that this is not in his best interest, but I am not absolutely sure about this. For one, our values are presently very similar, and we have much in common. In fact, I have never known anyone so similar to me. However, his life has been somewhat different from mine, and Allah has mercifully protected him from some choices I had to make. What I want more than spending my life with this man is for him to be at ease with his decision to marry me, and to feel that it is religiously correct or permissible for him to do so. Is that possible?