My parents don’t approve

So I’ve been messing with this guy for the last few years sneaking around. And recently we made it known that we wanted to be together . We are tired of sneaking around and only hanging out when No one knows . My parents are going crazy and trying to keep me away from him . He’s 30 and I’m 20 . Which is completely legal but my parents are going way to far . They don’t want me with him because he went to jail . And they even went as far as calling his probation officer . I don’t know what to do .. I’m 20 years old I shouldn’t have to listen to anyone and I feel like I need to make my own decisions. They have known him for years too so they should know he’s a great guy and he really does love me . And they are just not having it . I feel trapped by them and have no clue what to do . Need advice ASAP