The huge obstacle was Gian's fear of being left again. His wife had left him and he was still in a lot of pain, that's why he sought Mishas services in the first place. In their current relationship, everything was certain. As long as they had a contract, Misha would still come. Feelings of love can change, as they did in his marriage and he didn't want that uncertainty again

the ending for therapist was a missed opportunity. although the tragic ending was a good one, it could have been better if they ended up together. as the best story in momentum in my opinion, i didnt see any huge obstacle in gian and misha having a relationship. but the author did a splendid job with elements of bdsm, loved it!!!