You cannot force your boyfriend into marriage. The relationship was clearly consensual, and your voluntary consent is evident from the circumstances of the case. The fact that you covered all expenses doesn’t carry weight because there is no evidence to establish that these expenses were incurred in exchange for a promise of marriage.
Therefore, it’s advisable not to engage in unnecessary legal proceedings that are unlikely to yield positive outcomes. Additionally, there was no contractual agreement between you and your boyfriend stipulating that he would marry you in return for your financial assistance.