"

 First point - it was not only treated as mental illness, but as criminal activity.
 Second point - you should only refer to 'homosexual romance' in the lead if there is a section that deals with 'homosexual romance' in the body of the text, as the lead is a summary of what is in the body, and having ten sources does not count for much unless the terms are unpacked somewhere in the main text.  All these seem to show is that people like Giddens (who is a notable sociologist, but no authority on sexuality, sexology,  LGBT studies in general or homosexuality in particular) use the term.  If there were a link to an article Homosexual romance, which shows the term can be taken for granted, fine - otherwise it needs to be dealt with in the article before it can be inserted into the lead. 
 Third point, my earlier comment about this was made with ironic and humorous intent, because I have only come across the term 'romance' used in this context, at conferences, ironically or critically.  Just because a term is used in sources does not mean that it can be used in the lead when it is not in the text, for example, ""Homosexuals deserve to be executed or tortured""   "