I doubt the basic personality changes a lot, life experiences of course change us and how that personality is expressed.
Is it that people change, or we just become more aware of who we and our spouses are? In the early phases of relationships I think we are more likely to overlook faults of our partners, and to try and conform ourselves to what we think our partners wants. The test of many marriages is how we weather that phase wearing off. My observations anyway... no expert.
If it is just the friendship you want to rekindle would it work to invite the both of them to dinner and get to know the husband? Make him more comfortable with your reconnection. I have reconnected with my ex and that is what we do, I always see her either with him, or with one of her kids present. Nice to have the friendship back, without any threat of rekindling the romantic part. Can work.