Hello Friend, Good that you are seeking a help.
Any relationship will last for long term only if there is trust, open communication, give and take between the partners . He needs to respect your open communication about your past relationship and accept it as a reality.
May be you both need a pre marital counseling support to handle such suitations better and take it positive.
Next Steps
Consult a psychologists directly or online. Feel free to reach out to me online through Practo app chat for further evaluation and recommendation.