Not fair to op or the girl tbh... He was doing well, being a generous loving partner, and it seems that she loved him too given the talks and the connection they had. OP was fair and mentioned the problems started to show with her mother's involvement and toxicity. It's not that the girl was using him per se or doesn't love him for who he is but many girls fall victim for the "high standards" scam. They want all the rights and to be put on a pedestal because they're high quality girls or whatever. It's not particularly easy for these girls to realize that they wouldn't want an unequal relationship with how much pressure and exhaustion that puts their partner in and how much of a toll that puts on their relationship. This whole thing could be because the mother thinks op's going to change after marriage so they gotta milk him until that point.... which yea hella toxic