Advice please ?

After we went through our miscarriage in February , I've thought a lot about a lot of different things . My SO and I are not married yet we tried and got pregnant . I've come to realize that I want to be married before we try to conceive again . And he wants to start TTC when I get off my meds (in September) I want us to try again and I have no problem with September being our start date . I just have come to want to be married before we actually try again . So my question is how do I tell him this ? Whenever I bring up marriage he just says that he will propose when he feels it's the right time , and when I was pregnant his father was pushing the marriage subject on him , so I know he won't want to talk about it . Any and all help with my situation is greatly appreciated !