Because you are using the verb "romperSE", which is reflexive. romper = to break something (usually deliberately) romperSE = something breaks The subject of the sentence is not the person who breaks the object, but the object itself. "Las gafas" is 3rd person plural, so we use the reflexive pronoun "se" and the 3rd person plural suffix of the verb "HAN roto". As for why "me" is usted in the sentence, Alejandro has explained it perfectly. So, it would be possible to say: --> (Yo) he roto mis gafas / (Yo) me he roto las gafas (I broke my glasses). --> Las gafas se me han roto (word by word, "the glasses broke for me / the glasses broke and I was affected by it"; better translated, "my glasses broke"). When we use the second sentence, we technically don't know WHO broke them because the subject is not explicit... But, we infer it. Everyone will understand that it was me who broke the glasses, but we would rather not say it explicitly because we don't want it to seem our fault!! That's why "he roto mis gafas" doesn't sound natural. It also makes it seem like you broke them on purpose. Another very similar structure using a different verb: Se me ha olvidado qué tenía que hacer (I forgot what I had to do!) (olvidar = to forget something; olvidarse = something is forgotten). Is it clearer now? :)

Hola Mike! About your question: in this case we use "se me" because it comes from the reflexive verb "romperse", so in english we have "i have broken MY glasses", we use "MY" because we are talking about my glasses so we need to say to whom belongs this glasses. In spanish we have reflexive verbs and their differents way to use them, so in this case we say "se me" (that will mean "to me or to myself") han roto las gafas, and we dont say "se me han roto MIS gafas" because we already said "se me" that means that is your glasses and not anyone's else. Another example and maybe you can see it clearer: "te he roto las gafas"=>"i have broken your glasses", we dont say "te he roto TUS gafas" cause we already said "te he", that means "to you". So i hope its clear for you. Nice question and i hope you're satisfied. Thank you

se me han roto se is used because if you have two objects. ("me' and 'se") in the same sentence se has to come first. Also it would sound weird if you said "les me han roto," to spanish speakers. it is awkward grammar. han roto is in the perfect present tense so you cannot put anything between these or it would sound weird. so it literally says " they have broken themselves to me." in spanish there are set expressions like "caerse" so for example "me cae bien Mark" literally means Mark falls well to me. but it really mean "Mark is good person." These is casual Spanish and some reflexives act as verbal phrases.