ayyo, நம்ம பார்ப்பார பசங்களே இப்படி தான்.... blessed with narrow minded parents.
hathim, there is more fear than practicality in what you are saying.
you want to change your parents' minds at this point, the way i know tambram parents' minds work, it is impossible. no amount of logic or reasoning is going to force them to give you their blessings, even grudgingly.
there are other ways to sidestep sahagothram, like the girl being 'adopted' by an uncle with different gothram. to me, all that is b.s. and in a way, cheating and unfair to your true love.
you guys are so lucky to find each other, and i think, even the thought of spinstership, is something that you should be ashamed to think about. you two should be focussing on how you can get together to form a life.
things that you should consider is how to manage a household, children, lifestyle and all of this filled with love and happiness. your parents, yes. they should not be displeased. but only upto a point.
i will give you another guarantee. in a while, when there is a baby involved, you will notice, how quickly all the anger etc. evoporates.
i think i have said enough hopefully, to light a fire of enthu in you. get going lad and none of the talk of brahmacharyam or spinsterhood. such talk is for losers and கோழைஸ்