Question. How do you handle the age differences and life spans of your tavs/romances in bg3?

Are you asking if I've made my Tavs age-equal to the romances I've picked for them? If so, then I've actually been very careful about that. Lore-wise, I can't stand the thought of my character dying hundreds of years sooner or living hundreds of years longer than their partner. So I adhered to D&D 5E lore. If you're interested, I've explained most of the lifespans below.

Serena, my canon character, is human and romanced Gale. In D&D, the average lifespan of a human is 120 years, but since she and Gale are both wizards, they could potentially live for thousands of years. It all depends on the magic they wield. Elminster, for example, is nearly 1,300 years old. Otherwise, they'll age alongside each other as equals.

Saska is a Seldarine drow. On average they last between 400-750 years, depending on if they survive and leave the Underdark. Saska has indeed left the Underdark, works as a bard, and romanced Karlach. Tieflings typically live to 150; however, Karlach has the potential to live longer since her body has been so drastically altered. Upon finding a permanent upgrade for her engine, it's possible she could live just as long as a drow, if not longer, as she's been touched by infernal technology.

Ez'ria is a githyanki fighter/storm sorcerer. This one was easy, since she romanced Lae'zel. With any luck, they'll both live to a nice, healthy 120 years old; the average lifespan of a gith.

Eilonwy is my redeemed Dark Urge half-elf. On average they last about 180 years. This one's a bit more complicated because I partnered her with Astarion, who's a pure high elf and a vampire. High elves live to an average of 750 years, and vampires/spawn are of course immortal. But I've given this a lot of thought. Eilonwy, for example, is a druid, and because of their connection to nature/magic, their aging slows to 10% of what they would normally age. This means Eilonwy has the potential to reach 1,800. I should also mention that there are cures to vampirism in D&D 5E, so I like to think they find one at some point during their travels.

Bakara is a tiefling sorcerer of the draconic bloodline. Another semi-easy one, since I partnered her with Wyll. As I mentioned before, tieflings typically live to 150, whereas humans live to 120. I headcanon that my tiefling was already 50 when she met Wyll; who, according to Larian, is 24 during the events of BG3. To clarify, tieflings are considered young adults by the age of 20 and full adults when they reach the age of 60. So despite being 50, she's mentally around the same age as Wyll.

Thalias is a high half-elf Selûnite cleric. Possibly the easiest one, since he romanced Shadowheart, who is also a high half-elf who becomes a Selûnite cleric (at least in my game). With Selûne's blessing, they could live however long she desires, but on average they'll both live to be 180.

I also made an adorable little deep gnome named Mira to sweep Barcus off his feet. I shall wait patiently for Larian or a clever modder to make him romancable. The average lifespan for gnomes is 350 years.

Halsin is a bit more complicated, since he's a pure wood elf and a druid. This means he could conceivably live to be 7,500 years old, which is wild. I do plan on doing a playthrough where I romance him, and when I do I'll be making a mysterious wood elf named Arawen, a warlock who made a pact with an ancient archfey. So in addition to living to 750; as per the average lifespan of her race, as long as her pact remains in tact, she will live as long as her patron allows.