Community groups exist for Thai people in a number of areas around Perth. Some are closely connected to the Buddhist temple while others are more general.
Once you start meeting people with Thai partners living here in Perth you will become aware of groups they are members of. As with any acquaintances you make, some will become close friends others just casual acquaintances. Some groups will be closely oriented to your needs and demographic and other may not. Take your time and all these things will come to pass.