Just now caught up. I guess I'm a party of one because I didn't mind the love declaration. I don't think it invalidates her marriage. You can love someone, and those feelings can be very strong, but still know that person's not the right life partner for you. Still, you might have the the urge to confess if you were under pressure to tell a secret, your life was on the line, emotions were running high, and the person was sitting right there.
Mostly I just liked it because I thought it was well-acted, and I liked the steadiness and compassion that Reid displayed during the interchange at the wedding.
But, then again, I'm a romance writer and unrequited love is kinda my favorite trope, so that could be coloring my opinion of it! LOL.