Bryan told Good Morning America during a FaceTime session with Rachel on Tuesday that it bothered him to see how "wishy-washy" Peter was about his level of commitment to Rachel, who made it known from the start of her The Bachelorette journey she didn't want to leave the show with just a boyfriend.
"It's always tough to watch your fiancee date 30 other men," Bryan said with a laugh.
"I actually didn't meet with Peter last night but I saw the final episode. Yeah, as a man, you feel a little frustration of how she was treated and the position she was put in for the simple fact that here I am, totally committed, totally invested, totally ready to start a real future with this woman."
The 37-year-old chiropractor from Miami, FL, continued, "And then on the other end, you have someone who is indecisive, wishy-washy, and at the same time, he's telling her he's in love with her and will propose. So, it was just tough to watch."
During Monday night's finale broadcast, Rachel was shown visiting Peter's hotel room in Rioja, Spain, at the end of their last one-on-one date together, before she had to choose once and for all between Peter and Bryan.
From a viewer's perspective, Rachel was looking to find out where Peter stood and whether he'd be ready for a marriage proposal the next day. But Peter admitted he wasn't ready to get engaged and wanted to just continue dating Rachel in the real world.
When Rachel made it known Peter was going to lose her as a result, he decided he would make the "sacrifice" and propose marriage to keep their relationship going and make her happy.
Rachel, however, wasn't pleased with the idea of a man proposing out of pressure, and she feared he'd grow resentful of her since his heart needed more time before getting engaged. Rachel therefore let Peter go in one of the most excruciating and emotional goodbyes the franchise has ever seen.
"You see the emotional breakup that Peter and I had, and he was ready to propose. But at that point, I knew that he wasn't the one for me and it was really important for me to not have two men standing up there at the end," Rachel said on GMA. "If I knew what I wanted to do, then I wanted to send that person home the night before."
Rachel added that seeing Peter on the live portion of the finale broadcast was "more frustrating" than anything else.
However, both Rachel and Bryan appear to be happily in love now, and she's rocking a three-plus carat, pear-shaped diamond rock on her ring finger.
"When I got that First Impression Rose, I was feeling very confident moving forward, and there really wasn't any issue moving forward in our relationship. So my confidence remained sky-high throughout and I didn't have any reason to think otherwise," Bryan explained.
"I was confident in our relationship," Rachel agreed, "but I went back and forth because I had to make the best decision for me and I wanted to make sure I made the right decision, which obviously I did."