Together For Eternity

Merlin and Arthur have loved each other for a long time and are finally admitting it to each other. But as always, nothing seems to go right. When Merlin meets someone from his past, he starts acting strange. Who is he? And more importantly, what does he want with Merlin? yes, its a merthur fic. dont like, dont read! please R&R! contains mpreg! in later chapters.