Ideally I suppose I'd like a three-part system: firstly voluntary civil partnerships for everyone (with a very wide range and not exclusively for actual and implied sexual relationships, e.g. some recognition that adults may effectively be living in partnership with parents who they are looking after, or that friends may be living together and as mutually dependent as husband and wife). Secondly, involuntary civil partnerships for the parents of children, and thirdly "marriage" meaning whatever religious types want to get up to in the privacy of their own church/mosque/temple or whatever, with no bearing on the couple's legal status.