Lieutenant Tristan LaPointe was away at sea for six months aboard HMCS St. John's. Now six months is a long time to be on a boat, even if it is the dope Halifax-based frigate LaPointe was on. Heck, it's a long time even if you're single and don't have someone waiting for you at home.
But for LaPointe, to be separated from someone you know you want to spend the rest of your life with, the 189 days aboard the vessel must've felt like torture.
Which is why he probably did this the second the St. John's docked and he arrived at the port.