Coolant leaks in 2000 Durango

Repaired coolant leaks in 2000 Durango last year (several freeze plugs replaced, etc.) for about $1500. Coolant started leaking again last month, and new estimate for repairs is $1700–again some freeze plugs need replacing. Have put sealant in, which seems to have stopped leaking. I am afraid this is only a temporary fix, though. Is it time to sell the car (130,000 miles)? We have two-year-old triplets, and I have been looking at getting a used MPV instead.