I am completely clueless about how this works at all so any basic info would be very helpful. I have a mortgage in my own name. I am cohabiting and have 2 kids in creche now (didn't back then). My partner lives with me and is late 40s. We could do with a bigger house... what are our options? Would I have to sell the current house? If I don't (it would rent really well, not much profit to be made from selling it, just clearing of mortgage and taking back deposit etc) how is the current mortgage and prospective rent factored into the calculations?